I’ve done second
do-release-upgrade. What I can share is to mess with
/boot folder contents:
You should have boot files in
/boot folder, but
do-release-upgrade makes problem with free space on that partition (in this case it should have mounted
/dev/mmcblk?p4). What you need to do is
umount /boot, clear the contents of that folder (should be empty already) and then do
do-release-upgrade. For fast eMMC (from Allnet China) it takes below 1 hour.
Surely, it would be nice to make a backup copy of the
/boot folder, what you can do by this command:
cp -ra /boot /boot.old
If the kernels differ you would need to connect eMMC/microSD to PC and copy all files from
/boot folder from 5th partition ext4 to root
/ folder of 4th FAT16 partition.
And that’s all! You have Ubuntu 20.04.1 LTS now!
For now the latest kernel is:
The above was verified.