my grub menu is 2 and a bit screens long, so in screenshot i am showing the back page of it, on what was then my prime partition, held by Elementary OS (aka EOS).
where the highlighted line is, is the start of what is generated by my custom.cfg file
SCREENSHOT 1 - WIZARD'S ELEMENTARY GRUB - CUSTOMISED
mine has 2 arcolinux and 3 manjaro because i like calling those up quickly, but your custom.cfg need only have the one arch-based distro listed to achieve the desired outcome.
in the textual output for custom.cfg i provided alex the top line says GNOME, simply because that is what he is using, but i actually choose KDE, 2nd from the bottom, to get Screenshot 2.
vrai, the UUID you insert is that of your root partition / , eg /dev/sda1 , /dev/sdb2, whatever
you can get that from in gparted from right-clicking the partition entry, choosing information and copy and paste, or other partition editors as they require; or else at terminal with blkid - linux mint allows just blkid, debian and manjaro
sudo blkid
in my case, to shorten the output i focus on grepping the manjaroes, and i am writing from Debian Buster so
sudo blkid
Code:
chris@debian9dot8-MATE-SSD:~$ sudo blkid | grep -i mjro
[sudo] password for chris:
/dev/sda8: LABEL="MJRO-GNOME-HDD" UUID="e5a2cc40-0196-444a-bf0b-6c31480b53e0" TYPE="ext4" PARTUUID="b3b37ae9-5f4b-47c5-aba5-0c1cc982f3bc"
/dev/sdb4: LABEL="MJRO-Xfce-SSD" UUID="a27c129a-48b7-4158-8165-27756f6736cf" TYPE="ext4" PARTUUID="f00b23d8-4747-4dad-a158-257d2814c26b"
/dev/sdb5: LABEL="MJRO-KDE-SSD" UUID="04f35396-2f79-4d56-a1f0-312f6713d408" TYPE="ext4" PARTUUID="6ece6a86-ef94-4c90-aa5f-4b759f5fa5e3"
/dev/sdc5: LABEL="MJRO18.4-Xfce-WD" UUID="2802ee45-58d5-44f2-bf0f-7283b33e20bd" TYPE="ext4" PARTUUID="a805468a-020e-4926-a294-d2bd1230a4ed"
/dev/sdc10: LABEL="MJRO-Cinn-WD" UUID="394c75db-d300-4b79-b9b8-21e9997e884a" TYPE="ext4" PARTUUID="58c19e1c-399b-4234-9223-7cd540e5751f"
/dev/sdc20: LABEL="MJRO-Deepin-WD" UUID="f79ecc0a-ad43-40c0-9dac-c88d3ad12d3a" TYPE="ext4" PARTUUID="fd0adcaf-4216-400e-b2e7-c30006eda5ef"
/dev/sdc28: LABEL="MJRO-MATE-WD" UUID="58c5f278-e6b9-49cc-ab90-e100261da3c2" TYPE="ext4" PARTUUID="9ac02a25-311c-4837-b58b-5c0983703570"
chris@debian9dot8-MATE-SSD:~$
the highlighted uuid is for manjaro mate, but i put it in as gnome in the text before, as said.
with my root partitions, i label (not name) them with gparted after install, so mjro for manjaro &c. this then appears in my file manager and console output, makes for easier navigation.
so i chose KDE from the screen with the attractive lady you did not notice, and i get
SCREENSHOT 2 - WIZARD'S CUSTOM.CFG PATH TO LAUNCH MANJARO
so custom.cfg provides a 2nd, full menu, not a submenu, with your chosen arch-based distro in primary spot, each distro has its own submenu for advanced options. this 2nd menu has its own timer countdown - i go with 10 secs but you can enter straight through. and this menu will launch any of my distros including the arcolinux and other manjaro
the 2nd menu is in the same order as the first except for that primary spot
if your partitions for different drives housing linux are named the same in gparted. mine differ between /dev/sdbx and /dev/sdcx for reasons i can go into elsewhere some time.
i'll go a little further into building that custom.cfg next post, but rest my arm for now, and
... more coffee
wiz