Have 5 linux machines at home. 3 with Fedora 34 and 2 with Fedora 35. 4 did the dnf update that included 5.16.16 and rebooted fine.
The one system didn't?? Have 3 machine I vnc into, and have one monitor that I connect when I need to look at them.
When I couldn't get to the machine after there was enough time to reboot, and pings failed. I connected monitor.
When screen came up, it was sitting at grub menu. Pressing enter had it load the 5.16.16 kernel with what seemed no issue. Then did a restart and again, it just got to the boot menu with no timeout? So had to press enter again. Did that 2 more times, same results.
Reinstalled the kernel but again. Same result. Looked at grub.cfg and didn't see anything, and /default/grub was same as other machines?
Looked at grubenv and that was showing boot_success=0 while all other machines had boot_success=1.
On my notebook it shows as beginning. # GRUB Environment Block # WARNING: Do not edit this file by tools other than grub-editenv!!! saved_entry=189711f94e78436d9618b891a8fce70e-5.16. 16-100.fc34.x86_64 boot_success=1 boot_indeterminate=0
Tried the grub-editenv that it mentioned, but program not found. There is a grub2-editenv, so perhaps a missed update for the grubenv??
Help didn't show much, so was going to change the 0 to 1 with hexedit, but I looked at grubenv and it had changed from 0 to 1 on its own in the time I took looking at things.
The other 4 machines did update with no problem, and reboot started with no intervention. Not sure why this one had it go to grub menu, and just sit there.
Haven't tried another reboot to see it the timeout will work next time, or if will have to continue hitting enter after any reboot??
Haven't had this issue with any other updates??
Thanks. Have a nice day.