SOLVED Freenas 11.3-U1 stuck at zpool set cachefile

[Cartesio]

Since today when I boot my NAS it doesn't get past zpool set cachefile of one pool. I found this old thread (https://www.ixsystems.com/community/threads/help-freenas-11-1-u2-stuck-at-zpool-set-cachefile.69374/) but I didn't understand the root cause.

Does it mean the boot disk is corrupted and I need to reinstall from scratch? I was able to boot to a shell in single user mode and run a scrub and it didn't find anything. I also tried to boot the original 11.3 installation but it didn't get past that command too. Or is the pool to be corrupted?

It looks it does get stuck in a Python script that waits forever, why it doesn't timeout after a while and signal an error? Is there any way to get past it, or get a shell when it is stuck to perform some diagnostics? I don't know *BSD very well.

 

[Cartesio]

"Solved" by booting into an older 11.2U7 (since 11.3 no longer boots from an USB install disk without UEFI) which still worked (unlike 11.3 Release). Then upgrading again to 11.3U1 after deleting their boot environments. I couldn't stay on 11.2 because unluckily I had upgraded the pools when 11.3 showed stable enough. I didn't notice before the new UEFI requirrment. At least I can now easily move data off FreeNAS.
But there was another issue. When after upgrading to 11.3U1 I imported the last saved configuration, as soon as FreeNAS rebooted it got stuck again at "zpool set cachefile". I had to repeat the process and avoid to import the configuration. I don't know if the settings db was corrupted (opening it in SQLite didn't show anything wrong), or one of the last settings applied triggered the issue.