I keep having this issue on a local Linux server. When I want to update the system, after it downloads the updates and it's ready to install them, it says the boot size is too small.
Review the boot size:
$ df -h Filesystem Size Used Avail Use% Mounted on /dev/sdb1 190M 151M 26M 86% /boot
Increase Boot Size
According to this discussion on the Redhat forum. Increasing the boot size is possible but it's not a supported method, as it might create instability in the disk.
The recommendation is backing up the system and choosing a larger partition with a fresh install. Redhat recommends at least 1GB for /boot.
It is obviously a valid advice. But doing this could take hours.
These are the options to reduce the size of Used space.
Remove Old Kernels
As seen here
$ dnf list kernel
This can take a few minutes. My output was:
Installed Packages kernel.x86_64 5.3.8-200.fc30 @updates kernel.x86_64 5.3.11-300.fc31 @updates kernel.x86_64 5.3.14-300.fc31 @updates Available Packages kernel.x86_64 5.4.8-200.fc31 updates
Remove the number of kernels:
$ sudo dnf remove $(dnf repoquery --installonly --latest-limit=-2 -q)
If this doesn't work. Try restarting. Then run again. Then try updating system again.
You can also try limiting the number of kernels to 1:
$ sudo dnf remove $(dnf repoquery --installonly --latest-limit=-1 -q)
Now it shows:
$ df -h Filesystem Size Used Avail Use% Mounted on /dev/sdb1 190M 114M 63M 65% /boot