Symptoms:
I was running a dual boot system with Windows 10 (2019 May version) and Ubuntu 19.04. Both systems are UEFI secure booted. In Ubuntu 19.04, all drivers except Nvidia GPU were installed with those came with 19.04 installation package. The Nvidia GPU driver was separately downloaded from PPA and signed by MOK.
Yesterday I upgraded Ubuntu 19.04 to 19.10 by update-manager -d. After automatically reboot, I found I cannot normally boot into Ubuntu from Grub. It stuck at a purple screen, with a black box printed: UEFI Stub: Secure boot enabled.
What I tried:
1. From advanced options in Grub, I found Ubuntu 19.10 cannot be booted using kernel 5.3 but was bootable using kernel 5.0.0-32.
2. I tried to add nomodeset to grub options but still stuck at the purple screen when normal boot.
3. I tried to disable secure boot from BIOS but still stuck at the purple screen when normal boot.
4. I tried to uninstall Nvidia-driver by booting into kernel 5.0.0-32 and made sure the driver for both kernels 5.3 and 5.0 were removed. But I still stuck at the purple screen when trying to normal boot.
What happened and what should I do to make kernel 5.3 usable? Thanks!
Sys Info:
Core X i9-9820X, ASUS Prime X299 Deluxe II, 128GB RAM, Nvidia GTX 1650 + Nvidia Titan RTX, 256GB SSD + 1TB SSD + 4TB HDD + 8TB HDD.
Best Answer
I'm the PO of this post and I've fixed the booting problem by updating the BIOS to the newest version.
My previous BIOS is the 2019 July version, but the lastest on ASUS website is the 2019 October version which adds support for Core X 10th generation (my CPU onboard is from the 9th generation).
I'm not sure how it has helped the booting problem, but it has made the kernel 5.3 bootable through the new GRUB. Maybe it's about the intel-microcode and it's an ASUS or X299 specific problem?