1. sudo apt update 2. sudo apt upgrade # to revert all what downgraded packages 3. do reboot test(battery mode) (3/10) failed at 2nd, 7th, 9th trial (4.15.0-1081-oem) 4. do reboot test, again(ac mode) (4/10) failed at 2nd, 4th, 7th, 10th trial (4.15.0-1081-oem) 5. sudo apt install shim=13-0ubuntu2 shim-signed=1.34.9+13-0ubuntu2 # downgrade shim only 6. do reboot test(battery mode (1/10) failed at 10th trial 7. do reboot test(ac mode) (6/10) failed at 1st, 3rd, 4th, 5th, 8th, 9th trial 8. do reboot test, again(battery mode) (6/20) (because it fails to boot up at 11th and 12th, I do 10 more reboot tests. BTW, it fails to boot up at 21st trial.) failed at 10th, 11th, 12th, 15th, 17th, 20th trial It looks like downgrade shim doesn't help.
9. sudo apt install grub-common=2.02-2ubuntu8 grub-efi-amd64=2.02-2ubuntu8 grub-efi-amd64-bin=2.02-2ubuntu8 grub2-common=2.02-2ubuntu8 grub-efi-amd64-signed=1.93+2.02-2ubuntu8 10. do reboot test(battery mode) (3/10) failed at 3rd, 6th, 9th trial 11. do reboot test(ac mode) (2/10) failed at 2nd, 8th trial Downgrade both grub and shim do not work. 12. disable TPM in BIOS(secure boot is off already) 13. do reboot test (4/10) failed at 3rd, 7th, 9th, 10th -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1880663 Title: Dell Latitude 7300 sometimes stuck at purple screen after grub and fails to boot up To manage notifications about this bug go to: https://bugs.launchpad.net/oem-priority/+bug/1880663/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
