Can't boot the system. Snap_core is not set

Good day yo all!
Could you please help me to solve the problem? Here is the my story
I am using Xubuntu 20.04 with kernel 5.4.0-39. Since I did not use snap it was uninstalled earier. One day there appeared a need to use an app from the snap so i install it by means of Synaptic. All dependencies were satisfied. Unfortunately after restarting the computer I was unable to boot into the system, getting an error “the reqired kernel commandline snap_core is not set” and being redirected to BusyBox shell and initframs. Will you be so kind as to help me to boot the system and completely uninstall the snap so that to make the system operable again?
To my regret, my knowledge of the Linux is far beyond sufficient to rectify the trouble myself.

While it is hard to tell what exactly you did install there, the only single package you need to install to get snap packages working should be the snapd package, nothing else…

It is very likely you installed some other packages beyond snapd that might belong to the boot process of Ubuntu Core embedded systems … to fix this you should be able to intercept your boot at the bootloader:

select the former kernel in the menu, and your system should be able to boot again … now in the booted system try to remove the packages you installed (if you installed from a terminal, the up arrow should have your history of commands, from there you should be able to find out what beyond snapd you installed).

Thanks for your answer! Snapd was installed, you can see it in the apt log.

Start-Date: 2020-07-04 16:12:32
Commandline: /usr/sbin/synaptic

Requested-By: zheny (1000)

Install: gnome-software-plugin-snap:amd64 (3.36.0-0ubuntu3), snapd:amd64 (2.44.3+20.04, automatic), apt-build:amd64 (0.12.47), gkdebconf:amd64 (2.1.0), apt-listchanges:amd64 (3.22), libappconfig-perl:amd64 (1.71-2, automatic)

End-Date: 2020-07-04 16:13:07

Start-Date: 2020-07-04 16:21:07

Commandline: packagekit role=‘remove-packages’
Requested-By: zheny (1000)
Remove: simple-scan:amd64 (3.36.0-0ubuntu1)

End-Date: 2020-07-04 16:21:12

Another bad thing that I have only one kernel installed, others I had removed to get some free space.
Seems there is only one way - reinstallation ((((

the issue you have isnt with snapd but with other packages you have installed (most likely initramfs-* packages that do not belong on a non-embedded install)

Thanks a lot! I see there is no way out but to reinstall the system(((