PC reboots immediately after GRUB (7 3700X / 5700 XT)

[sker]

I am experiencing a persistent boot loop across multiple distributions (Ubuntu 25.10, Arch, and Debian). After selecting a boot entry in GRUB, the screen flashes a single underscore for a few seconds and the system immediately reboots.

This issue started after a power outage caused a BIOS reset (I did not have an CMOS battery installed). I encountered this exact issue a year ago, which was seemingly resolved by a BIOS update, but re-flashing the BIOS this time has not helped.
Specs:

• Ryzen 7 3700x
• Radeon RX 5700 XT
• 16 GB DDR4
• 1 TB NVME

I have attempted to isolate the issue by modifying boot parameters and BIOS settings:

• Boot Parameters:
  • Removed quiet and splash
  • Tried with nomodeset, iommu=off, acpi_enforce_resources=lax
  • acpi=off (only worked on arch)
• BIOS changes:
  • Disabled Secure Boot and TPM
  • Disabled C-State Control, IOMMU, ErP Ready, XPM
  • Reflashes BIOS to latest version (F67)

I hope someone can help me.

 

[Condobloke]

G'day sker, welcome to Linux.org

Do you have a cmos battery in place now ?

Is this a dual boot ?

your bios is configured to work in UEFI mode, so the partition scheme should be GPT
i do not know if the lack of a bios battery would allow settings like these to be altered.....but......best that you check

 

[sker]

G'day sker, welcome to Linux.org

Do you have a cmos battery in place now ?

Is this a dual boot ?

your bios is configured to work in UEFI mode, so the partition scheme should be GPT
i do not know if the lack of a bios battery would allow settings like these to be altered.....but......best that you check

I have installed a CMOS battery, which holds the charge to save the BIOS settings. My NVMe is empty currently.

 

[Condobloke]

My NVMe is empty currently.

• Ryzen 7 3700x
• Radeon RX 5700 XT
• 16 GB DDR4
• 1 TB NVME <<<<<<<....this one?....is this the drive that you are installing on?

If it is, then there is no OS.

After selecting a boot entry in GRUB,

That would indicate there IS an OS there.

wth

Best to check the health of your nvme/ssd

https://www.baeldung.com/linux/ssd-verify-health