Till you figure out a solution or root cause of this issue, for the time being you may disable Secure Boot in BIOS to avoid this issue.
Ubuntu Linux
Linux for Human Beings.
Ubuntu is a popular Linux operating system for PC / mobile devices, etc.
Developed by Canonical & based on Debian (another older Linux OS) which is known for it's rock solid stability.
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I have only Ubuntu, I had to disable SecureBoot anyway to keep the NVIDIA drivers from giving me a black screen with a blinking cursor after a RAM upgrade.
@KarnaSubarna Hi..secure boot is already disabled (tried re-enabling and then disabling but no change).
Tried formatting everything and Installing fresh Win11 (latest updated) with Ubuntu 23.10 but problem still persists.
Same issue as reported here[1]? [1] https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/2030810
@KarnaSubarna Yes this is the exact problem. I hope Ubuntu will fix it soon. 😥
Thank you so much for the reply and details❣️❣️❣️