Question Toshiba laptop won't boot without alternating between UEFI x CSM first. Bizarre behaviour.

[barataaway]

Hi All,
My laptop is a Toshiba Portege R930 (i5, 16Gb RAM, 500Gb SSD), running Red Hat Enterprise Linux 8.4. It uses UEFI settings to boot.

Recently I had to boot a different OS (loaded from USB stick directly to memory) that required CSM (legacy) BIOS configuration. Everything went fine. After using it, I've reverted BIOS back to UEFI.

However, after rebooting to go back to RHEL, the system got in an eternal loop and couldn't start.

I have managed to get around this strange (and annoying) behaviour by changing the BIOS to CSM, trying to start (getting an error, as expected), then changing BIOS back to UEFI. This time the system shows me the kernel list and allow me to boot.

Now, every time that I try to reboot my laptop I have to do the same thing:

• change bios to CSM
• try to start (error)
• change back to UEFI
• start RHEL.

Has anyone had a similar problem before or have any idea on how to fix it?

Thank you
Cheers!

 

[Mohamed Grwash]

You can use "MiniTool Wizard" to change MBR to GPT mode
Then ur OS work very perfectly

 

[barataaway]

You can use "MiniTool Wizard" to change MBR to GPT mode
Then ur OS work very perfectly

Hi Mohamed, my boot disk already uses GPT, but thank you for the suggestion.