Post install Grub on separate partition

[mike_linux]

Hi guys, I have two operating systems one is Ubuntu 18.04. and the other is Win10 home. Both of them are installed on two separate SSD discs (both discs have 500GB capacity). I have installed them on separate discs because I don't want to hurt one of the OS if I need in the future to reinstall one of them. The problem is that every time I want to switch the OS I have to go to the bios and switch the boot order which is getting annoying. I have divided the Ubuntu disc as follows swap partition 6GB (I don't use hibernating), home partition 15GB and the rest is for the main partition. Is there any possibility to post-install grub without touching any of the two operating systems?.

 

[Condobloke]

G'day mike, and Welcome to linux.org

I can imagine that would get annoying really quickly!!!

I run Linux mint 20, which is an offshoot of Ubuntu....so the two are very similar

one major difference is I do not dual boot (when I left win 10 behind...I seriously left it behind)

I also know precious little about grub......ther4e are others who will likely talk your ears off about that.

However...
1. Do you have Timeshift up and running on Ubuntu ?
if not....do it.
It will be amongst the apps in Software manager.
Set it up to save the snapshots to an external hard drive. There is no need to have dozens of snapshots....probably two per month is enough. (I keep two/month, and then delete one from the previous month...so I always have three)
If you need a hand to set it up....please just ask

2. Also in Software manager there is this...

SO....my point is this.....
Set Timeshift up so if anything goes south, you can simply Restore a snapshot of your Ubuntu, and all will be as if nothing happened. (yes, it is that good)

Then, in Ubuntu ...access the Grub-pc version 2 in software manager, and install it.

Once that is done, reboot and see what has happened.

There is another member online atm... @wizardfromoz who will 'see' this post and come and make any corrections if indeed I have missed anything

)

 

[wizardfromoz]

G'day Mike and welcome to linux.org ..

There is another member online atm... @wizardfromoz who will 'see' this post and come and make any corrections if indeed I have missed anything

That would be moi

I'll put together a few questions while I crack open a beer and be back

Chris Turner
wizardfromoz

 

[wizardfromoz]

Timeshift may not be in Software Centre with 18.04, it is in 20.04 but Mike can tell us.

If not there, go to

https://github.com/teejee2008/timeshift

There, scroll down to Installation - Debian-based Distros

and follow the instructions.

Better is to set up a Timeshift Partition, before you first run it, and then when you run the Wizard, direct it to that Partition.

If you do not, it will create snapshots on your Home partition by default, and 15 GB will not last long.

I'll ask some more questions in a separate Post, and offer options.

Wizard

 

[wizardfromoz]

OK questions, Mike:

1. Can you boot into your Ubuntu, issue the following command at Terminal, and report back the output?

dpkg -l | grep grub | grep ii

Mine looks like this on a Linux Mint

chris@Tina-Xfce-HDD:~$ dpkg -l | grep grub | grep ii
ii grub-common 2.02-2ubuntu8.19 amd64 GRand Unified Bootloader (common files)
ii grub-efi-amd64-bin 2.02-2ubuntu8.19 amd64 GRand Unified Bootloader, version 2 (EFI-AMD64 binaries)
ii grub2-common 2.02-2ubuntu8.19 amd64 GRand Unified Bootloader (common files for version 2)


Reason: grub-pc is not for UEFI based computers. If Mike is running Windows 10, it is likely (but not certain) that he is running it under UEFI conditions.

2. Do you know if you have GParted (the GNOME Partition Editor) installed yet?

If NO, then

sudo apt-get -y install gparted

If YES, or when installed, can you open it? Top right-hand side there is a switch that will allow you to look at both of your SSDs, one at a time. Take a picture or screenshot of each SSD's partition scheme and post it up here.

I am expecting that each one of the drives will have an ESP (EFI System Partition) on it, and if so, that is a good way to safeguard the individual operating systems.

Cheers

Wizard

 

[captain-sensible]

Install both OS on one disk - on seperate partitions, put GRUB either from Windows or Ubuntu, and enjoy dual booting via GRUB.

theres some reports i've seen with a dual boot on one disk that when Windows 10 does updates it manages to vandalize the integrity and boot of Linux .

 

[mike_linux]

Hi guys, I am glad to be here (@wizardfromoz How was the beer?) .

Wao, there is a lot of information and I have to look over in the evening (here in Greece it is 2:00 pm) while I am drinking coffee. Thank you for the provided help which I will handle soon and get back if the problem is fixed. At first, I will install Timeshift and shrink my main partition (over 400GB on the Ubuntu SSD) to get the space for the snapshot. Then I will install grub. By the way on which partition should I install it on Ubuntu or Windows?. If there is any other alternative of grub I have no problem checking this out, too.

 

[captain-sensible]

my instinct would be the ubuntu partition

 

[mike_linux]

Ok, I will do so. Which program can I use to shrink my main partition for the snapshot?. I have seen that there is an app called Gparted Live CD (https://howtoubuntu.org/how-to-resize-partitions-with-the-ubuntu-or-gparted-live-cd) which I can install via the package manager. Is this the right one most people use?.

@wizardfromoz I had to disable the UEFI in the bios, because otherwise
Ubuntu did not boot.

Guys, this is my partition table of the Ubuntu ssd. My home is 40GB not 15 as I wrote before (could not imagine right). Should I resize the / partition or the /home one what do you suggest?.

Linux Partition

SCREENSHOT 1 - LINUX SSD

By the way here is an article which describes that I cannot partition Ubuntu while it is running. Is that true?: https://askubuntu.com/questions/116351/increase-partition-size-on-which-ubuntu-is-installed/116367

This is the Windows partition which is on a nvme SSD disk

SCREENSHOT 2 - WINDOWS 10 SSD

@wizardfromoz issuing this command you have given me dpkg -l | grep grub | grep ii I get this output in my terminal:

SCREENSHOT 3 - GRUB PACKAGES ON SYSTEM

 

[mike_linux]

Guys, I don't like my partitions for example the home partition of 40GB is very small and with gparted live cd I could not change the size because the partition resists at the end of the disk space. So, I have decided to reinstall all from the beginning (a tedious job) and also instead of Ubuntu 18.04. LTS I will install the new 20.4. LTS.

EDIT: For the first time I have left the ubuntu 18.04. lts version because it would take me some time to install 20.04. lts (will do it another time). Nevertheless, I have taken a snapshot on my new partition (named BACKUP LINUX) and tried to install grub version 2 but there is no such version available. More precisely I get an error message that grub2-mkconfig is not available. Via the software package manager there is only the old version available . Is there any other link where I can get the second one?. I have searched a little bit, but did not find anything. I have tried this here :

Grub2/Installing - Community Help Wiki

Bootloading with GRUB2

GRUB2 is the latest version of GNU GRUB, the GRand Unified Bootloader. A bootloader is the first software program that runs when a computer starts. It is responsible for loading…

docs.fedoraproject.org

 

[wizardfromoz]

G'day Mike

I have taken a liberty and undeleted your Post above because it contains information that is important to where we are. If we get confused we will work through it.

I have also labelled your screenshots so that we can more easily refer to them.

Good screenshots, thank you, they make things a lot easier

The Windows setup has me somewhat curious. The left pane of the GParted shot in Screenshot 2 shows the disk as msdos, which is basically MBR (Master Boot Record) structure, which means that Windows 10 has been installed under that environment instead of under UEFI, which it prefers.

I know that can be done, but I am not familiar with the process (don't use Windows). I do however know someone who has done that, and he may be able to assist.

@stan if you are in the neighbourhood soon, can you take a look at this Thread please?

I have left the ubuntu 18.04. lts version because it would take me some time to install 20.04. lts

If that install is still working, perhaps you can give us the output from Terminal of

inxi -Fxz

That will amongst other information give us details of the brand name and model number of your computer, so we can check for installation problems.

When you get the output, if you have a Menu bar on your Terminal, choose Edit -Select All, then right-click and choose copy for the text.

Come into this Forum, and on the Toolbar at top of your reply pane, there is an icon with 3 dots and a down arrow right of the smiley face. Click that, choose Code and paste the output.

I will outline in my next Post what I was looking at suggesting to you, which involves a process called grub-install - but we will look at that soon.

Cheers

Wizard

 

[mike_linux]

Hi guys,

I have taken a liberty and undeleted your Post above because it contains information that is important to where we are. If we get confused we will work through it.

No problem @wizardfromoz I thought it was confusing that's why I deleted this message.

Good screenshots, thank you, they make things a lot easier

THX, I am trying to give as much clear information as I can . By the way the forum structure and handling is so easy and exemplary. A lot of other communities should from it. For example, here you do not have to upload any screenshot on another space and link to it.

The Windows setup has me somewhat curious. The left pane of the GParted shot in Screenshot 2 shows the disk as msdos, which is basically MBR (Master Boot Record) structure, which means that Windows 10 has been installed under that environment instead of under UEFI, which it prefers.

I know that can be done, but I am not familiar with the process (don't use Windows). I do however know someone who has done that, and he may be able to assist.

@stan if you are in the neighbourhood soon, can you take a look at this Thread please?

Yes that is right maybe I did not considered that the partition is of msdos when I did the install (some time ago), but it still works without any problem. I don't know if this problematic for grub.

If that install is still working, perhaps you can give us the output from Terminal of

Ordinarily, I wanted to install 20.04. LTS from scratch but as I do machine learning and deep learning, I had read that the 10.2 CUDA version cannot be installed on 20.04. LTS (maybe now it is possible I will check this if I manage that grub can boot both systems, because this is my primary problem now )

Here is the output of the command execution

SCREENSHOT 1 - inxi -Fxz COMMAND EXECUTION IN TERMINAL

mike_ubnt@ubuntu-18:~$ inxi -Fxz
System:    Host: ubuntu-18 Kernel: 5.4.0-54-generic x86_64 bits: 64 gcc: 7.5.0
           Desktop: Gnome 3.28.4 (Gtk 3.22.30-1ubuntu4) Distro: Ubuntu 18.04.5 LTS
Machine:   Device: desktop System: ASUS product: All Series serial: N/A
           Mobo: ASUSTeK model: X99-DELUXE II v: Rev 1.xx serial: N/A
           UEFI: American Megatrends v: 0801 date: 06/28/2016
Battery    hidpp__0: charge: N/A condition: NA/NA Wh
           model: Logitech M720 Triathlon Multi-Device Mouse status: Discharging
           hidpp__1: charge: N/A condition: NA/NA Wh
           model: Logitech K780 Multi-Device Wireless Keyboard status: Discharging
CPU:       6 core Intel Core i7-6800K (-MT-MCP-) arch: Broadwell rev.1 cache: 15360 KB
           flags: (lm nx sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx) bmips: 40776
           clock speeds: max: 3800 MHz 1: 1981 MHz 2: 1203 MHz 3: 1200 MHz 4: 1203 MHz 5: 1200 MHz 6: 1199 MHz
           7: 1323 MHz 8: 1199 MHz 9: 1200 MHz 10: 1199 MHz 11: 1201 MHz 12: 1199 MHz
Graphics:  Card: NVIDIA GP104 [GeForce GTX 1080] bus-ID: 01:00.0
           Display Server: x11 (X.Org 1.20.8 ) drivers: nvidia (unloaded: modesetting,fbdev,vesa,nouveau)
           Resolution: [email protected], [email protected]
           OpenGL: renderer: GeForce GTX 1080/PCIe/SSE2 version: 4.6.0 NVIDIA 450.80.02 Direct Render: Yes
Audio:     Card-1 Intel C610/X99 series HD Audio Controller driver: snd_hda_intel bus-ID: 00:1b.0
           Card-2 NVIDIA GP104 High Definition Audio Controller driver: snd_hda_intel bus-ID: 01:00.1
           Card-3 Creative Labs Sound Core3D [Sound Blaster Recon3D / Z-Series]
           driver: snd_hda_intel bus-ID: 0d:00.0
           Sound: Advanced Linux Sound Architecture v: k5.4.0-54-generic
Network:   Card-1: Intel Ethernet Connection (2) I218-V driver: e1000e v: 3.2.6-k port: f000 bus-ID: 00:19.0
           IF: eno1 state: up speed: 100 Mbps duplex: full mac: <filter>
           Card-2: Intel I211 Gigabit Network Connection driver: igb v: 5.6.0-k port: d000 bus-ID: 0c:00.0
           IF: enp12s0 state: down mac: <filter>
           Card-3: Broadcom and subsidiaries BCM4360 802.11ac Wireless Network Adapter driver: wl bus-ID: 0e:00.0
           IF: wlp14s0 state: dormant mac: <filter>
Drives:    HDD Total Size: 5013.0GB (1.0% used)
           ID-1: /dev/nvme0n1 model: Samsung_SSD_970_PRO_512GB size: 512.1GB
           ID-2: /dev/sda model: WDC_WD4003FZEX size: 4000.8GB temp: 35C
           ID-3: /dev/sdb model: Samsung_SSD_860 size: 500.1GB temp: 0C
Partition: ID-1: / size: 336G used: 8.1G (3%) fs: ext4 dev: /dev/sdb5
           ID-2: /home size: 40G used: 33G (88%) fs: ext4 dev: /dev/sdb3
           ID-3: swap-1 size: 6.00GB used: 0.00GB (0%) fs: swap dev: /dev/sdb6
RAID:      No RAID devices: /proc/mdstat, md_mod kernel module present
Sensors:   System Temperatures: cpu: 24.0C mobo: N/A gpu: 1.0:43C
           Fan Speeds (in rpm): cpu: N/A
Info:      Processes: 367 Uptime: 10 min Memory: 1743.9/32024.0MB Init: systemd runlevel: 5 Gcc sys: 7.5.0
           Client: Shell (bash 4.4.201) inxi: 2.3.56
mike_ubnt@ubuntu-18:~$

THX for further help and Greetings

 

[stan]

@stan if you are in the neighbourhood soon, can you take a look at this Thread please?

You rang? I am currently installing Win 10 in a desktop on one hard drive, and I'll follow that by installing Ubuntu 18.04 on a separate hard drive (internal). This desktop is so old it does not have UEFI. With any luck, I'll post a couple of screenshots of GParted in a bit to show my results.

 

[stan]

Okay, I'm back. First, let me say that every computer (and UEFI/BIOS) is different, and this is a constant struggle when folks cannot do what we think they should be able to do. Ubuntu should be able to install and work in UEFI mode, and even with Secure Boot enabled. But I know that is not true in all cases.

Mike's SCREENSHOT 3 above (post #9) shows that GRUB files are present. GRUB is the bootloader normally installed by Ubuntu. Mike can boot Ubuntu (via BIOS boot menu) so GRUB is installed and working.

With a fresh install of both Win 10 and Ubuntu 18.04.5, each on it's own hard drive, I have a similar situation. I need the BIOS boot menu to choose Ubuntu, or else Windows starts by default. Let me remind Mike, and any other viewers, that using the BIOS boot menu is an acceptable method, and in some cases it is the only method that will work (or so I've read). With a dual-boot system, one OS must be the default, and some action must be taken to boot the other OS. So my initial install is similar to Mike's.

However, in my BIOS settings, I was able to switch which hard drive is the boot default. I've read that not everyone can do this, but it was a simple change for me. After saving this change in BIOS, now GRUB starts first. And in my case the GRUB menu also shows Windows, so I can "arrow down" to select Windows if I want it, or else Ubuntu will be the default. @mike_linux, do you see the GRUB menu when you choose Ubuntu from your BIOS menu? And if you do see it, do you also have the Windows option there? Maybe you also can find a BIOS setting to change the hard drive boot order, if you want Ubuntu to be the default OS to start at boot up.

I should point out that for the same reason as Mike, I specifically installed the GRUB bootloader on the hard drive that has Ubuntu, although I'm pretty sure that it would work to install it on the Windows hard drive, and then GRUB would be the default from the beginning. Both methods have pros and cons. Ubuntu and its GRUB bootloader are self-contained on the 2nd hard drive, but if I remove it and put it into another computer, I believe it will fail with a grub> or grub rescue> prompt if it does not also see a Windows drive. This can be fixed, but its a headache we often see on this forum. If I remove the Ubuntu drive, the Windows drive should still work fine. Windows is pretty oblivious to Linux and other bootloaders.

Looking at Mike's GParted screenshot, I agree that I don't think he will be able to expand his /home partition. But more than that, I wonder how/why that partition structure came about? There is no need for an extended partition to be used, nor a swap partition. Did Ubuntu do this on it's own?

There are different opinions about the value of a separate partition for /home, and I will say that I'm absolutely opposed for new Linux users to do this. The evidence is here right now. New users just don't have the experience yet with the Linux ways of doing things, or even how drives and partition are identified (/dev/sda1, /dev/sdb2, etc). All the major Linux distros give you the power to manually partition your system, but most will recommend that new users just use a single / partition and let everything go inside of that. And that is totally what I recommend and it's also what I do myself. If installing a dual boot system on a single hard drive, most major distros will give the option to "install alongside Windows" and I also strongly recommend that instead of the "something else" choice. The distro developers have really made installing Linux much easier this way, and much less prone to failure.

Okay, maybe these screenshots will help Chris understand better the Windows 10 install on a msdos hard drive. He is far more knowledgeable than I am with this stuff. And maybe he will understand why GParted shows the Windows boot flag on /dev/sda1 (50 MiB) when Windows Disk Management shows the boot partition on the 698 GB partition. I took a few more screenshots during the Ubuntu install process, but I don't think they will contribute any more at this point.

SCREENSHOT 4 - stan's WINDOWS DRIVE - DISK MANAGEMENT

SCREENSHOT 5 - stan's WINDOWS DRIVE - GPARTED

SCREENSHOT 6 - stan's LINUX DRIVE - GPARTED

 

[wizardfromoz]

Very many thanks for that, stan

I will digest all that - have to go out for a bit and be back a little later in my morning with more. I'll label your screenshots 4, 5 and 6.

Can you tell me - if you choose the Install Alongside Windows option, do you still get the interactive option to set the device where Grub is installed, as, say /dev/sdb in Mike's case?

Is that what you meant when you said

I specifically installed the GRUB bootloader on the hard drive that has Ubuntu,

?

Cheers

Chris

 

[mike_linux]

Hi stan, and THX for the help .

Okay, I'm back. First, let me say that every computer (and UEFI/BIOS) is different, and this is a constant struggle when folks cannot do what we think they should be able to do. Ubuntu should be able to install and work in UEFI mode, and even with Secure Boot enabled. But I know that is not true in all cases.

Yes, that is right I had to switch to bios mode because in UEFI mode Ubuntu did not boot.

@mike_linux, do you see the GRUB menu when you choose Ubuntu from your BIOS menu? And if you do see it, do you also have the Windows option there? Maybe you also can find a BIOS setting to change the hard drive boot order, if you want Ubuntu to be the default OS to start at boot up.

No, I don't. I can't see any boot menu. I have switched the boot order in the UEFI bios to boot at first from my Ubuntu drive (860 Evo), but there is no boot menu coming up at the start time.

I should point out that for the same reason as Mike, I specifically installed the GRUB bootloader on the hard drive that has Ubuntu, although I'm pretty sure that it would work to install it on the Windows hard drive, and then GRUB would be the default from the beginning. Both methods have pros and cons. Ubuntu and its GRUB bootloader are self-contained on the 2nd hard drive, but if I remove it and put it into another computer, I believe it will fail with a grub> or grub rescue> prompt if it does not also see a Windows drive. This can be fixed, but its a headache we often see on this forum. If I remove the Ubuntu drive, the Windows drive should still work fine. Windows is pretty oblivious to Linux and other bootloaders.

I personally would prefer to leave grub on the Ubuntu drive because it is more related to Linux than to Windows (I believe). But I don't know how to add an entry for Windows 10 to the Grub boot loader (if I manage to show the bootloader at startup).

Looking at Mike's GParted screenshot, I agree that I don't think he will be able to expand his /home partition. But more than that, I wonder how/why that partition structure came about? There is no need for an extended partition to be used, nor a swap partition. Did Ubuntu do this on it's own?

I have created the 6GB swap and home partitions because I have read and looked at youtube videos to get the work done. When I will install in future the 20.04. LTS version I will leave as you wrote only the \ partition (no swap and no home partition anymore). When I installed Ubuntu I chose the 'something else' method because I didn't want to install Windows 10 and Ubuntu alongside on the same disk and I also don't prefer that (that is the reason why I bought the second EVO disk).

 

[wizardfromoz]

Morning (for me) Mike, I love that Tux penguin avatar

When I installed Ubuntu I chose the 'something else' method...

That is what I suspected, and I understand your reasoning, you are doing fine.

It will be late where you are, so you could catch some zzz's and come at this fresh (always a good idea).

When I get back from my excursion, I'll outline a couple of options to leave for you, and stan (who is US-based I think) can run through them as well, and between us, we've got your back.

Cheers

Wizard

 

[mike_linux]

It will be late where you are, so you could catch some zzz's and come at this fresh (always a good idea).

Yes, here it is 1:19 midnight and I will go to bed now otherwise I will not stand up in the morning . Good night from Greece to all and will look after the post tomorrow.

 

[stan]

I've caught at least one mistake in my work. I'll review and be back soon with an update.

 

[stan]

My apologies, I'm getting very rusty with this stuff. But the best way for me to find out something is to do it myself, if I can. Remember what I said about all computers and UEFI/BIOS being different. Since I am currently testing a MBR/BIOS only system, a GPT/UEFI system may behave differently. This is in case Mike (or other viewers) have similar problems but are not helped by my comments. Sometimes you have to keep trying different things to see what works for you on your system.

I started over. A fresh install of Windows 10 first, with my #2 hard drive physically removed. This allowed me to better answer this question from Chris:

Can you tell me - if you choose the Install Alongside Windows option, do you still get the interactive option to set the device where Grub is installed, as, say /dev/sdb in Mike's case?

The short answer is no. "Install alongside Windows" is really a tool to put both systems on the same hard drive, and preferably WITHOUT pre-partitioning from Windows to create space for Linux. I keep seeing that advice to create the space first, but then that practically demands the "something else" method of install. Let Linux do the automatic partitioning with the "alongside" option. If Linux is on another drive, it is not "alongside" anymore. Using this feature brings up a rectangular box that is split roughly in the middle indicating half Windows, half Linux. You can click and drag the divider bar in the center to change the size of the partitions that are about to be created and resized. This will, of course, put GRUB on the same hard drive which is identified as /dev/sda. However, there is an "advanced option" where you can choose specific partitions. Since I had 3 partitions automatically created by the Windows install, it would let me install GRUB into any of those. I think this is a BAD IDEA on an MBR system, but it may be useful at this step to put GRUB into a proper EFI partition. This "advanced option" basically just returns you to the "something else" screen. But the "alongside" feature is very good for new users as it usually works well on a single hard drive and does not require much knowledge or interaction from the users.... just drag the slider bar to set the partition size.

No, I don't. I can't see any boot menu. I have switched the boot order in the UEFI bios to boot at first from my Ubuntu drive (860 Evo), but there is no boot menu coming up at the start time.

What may be a very simple solution is to again make your Ubuntu hard drive the one to boot first in your BIOS settings. Since you do not see the GRUB menu (just a blank purple screen, I guess?) and then Ubuntu boots. With Ubuntu running, open a terminal and give this command: sudo update-grub. It should finish quickly. Then reboot and see if the GRUB menu is now visible. If it is, I think you will be able to "arrow down" to Windows and select it to boot, or leave it alone and Ubuntu will boot automatically after about 10 seconds. GRUB does not show a menu when it only sees one OS, so I think it may not see Windows, for whatever reason. There is a way to force the GRUB menu, but it is tricky and not worth the effort of the above works. I don't think you would see Windows yet, even if you forced the menu.

I have created the 6GB swap and home partitions because I have read and looked at youtube videos to get the work done.

I understand that Mike, and I hope I didn't offend you. New users find info in many way, and some are better than others. And even among "experts" there is difference of opinions. It wasn't that long ago that Wizard taught me that the swap partitions are no longer needed (usually) because many distros are now creating a swap file instead, including Ubuntu. Things change, and it's hard to keep up. You would easily find others here who more support a separate /home partition, and there are good reasons. It's just my opinion that installing everything under / is better for a beginner. If you run out of space then, well, WOW!

Okay, let me recap my install. Everything was as before, Windows and Ubuntu on separate drives, and I needed the BIOS boot menu to start Ubuntu. The Ubuntu bootloader was on the same drive (/dev/sdb) as Ubuntu. I then physically removed that drive. Upon booting, Windows started, as I expected. Whew! This helped to confirm that each drive was separate and self-contained.

What I was wrong about was that I thought this removed drive would fail to boot in another computer. So what I did was to physically remove my #1 drive (Windows) and install my #2 drive back in. And it worked also, to my surprise. But I also did not get the GRUB menu anymore, and it just booted straight into Ubuntu. I rebooted and "forced" the menu to appear and Windows still showed there, but I did not try to choose it, not knowing what might happen. So, as I described above, I booted Ubuntu, and did sudo update-grub in a terminal. On the next reboot, and forcing the menu again, I found that Windows was properly removed.

Besides the chance that these things may not work the same for other people, let me also say that GRUB can be picky too. I made a common mistake a little while ago... I deleted the (only) partition in my #2 (Ubuntu) drive instead of physically removing it, wrongly thinking that Windows would still boot. IT WOULD NOT, and I got the grub rescue> prompt as a reward. That's when I started over.

Many people have reported that Windows updates will mess up their GRUB boot options, and make it so only Windows will boot. I have not had this happen, but I don't really run Windows enough to find out. If it happens, maybe the BIOS boot menu will still work, and sudo update-grub will again restore the boot choices. It would be the first thing to try, anyway.