Hi!

I think the first thing to mention should be: Do not delete any file in the directory /UNIONFS or its subdirectories if you do not know whether it is essential. Always use the package management software to remove the whole package if the file is a member of a package.

The short answer to your question is you have to reboot your system with the noimage cheatcode. Then mount your overlay file as a loop back device and copy libc-2.17.so from /lib/i386-linux-gnu to the right place in your overlay file. Do not forget to create soft links to this file if you have deleted them before.

The real commands depend on the type of overlay you are using. Is it an unencrypted overlay or an encrypted overlay or a whole overlay partition?