The following helped:
Two files:
1) Update_jailbreak_hotfix_1.16.N_install.bin
2) Update_KUALBooklet_ff4134d_install.bin
Dropped to mrpackages, after -> ;log mrpi in the search bar, and it worked! Now I can open KUAL and KOReader.
That is, it turns out that Jailbreak was saved and it remained?
Is it possible to block updates, and at the same time have access to the Internet (I sometimes send books to the device via Send to Kindle:
https://www.amazon.com/sendtokindle)?
Or do I need to roll back to an older version?
Thank you!