Stuck loading extensions on boot

Hi, i'm working on a personal rework based on Slimmer (https://github.com/terba/slimmer), a display controller for LMS by Terba.
I compiled my code directly on PI with success. So I created the tcz extension with the tool mksquashfs and copyed tcz in /tce/optional.
After that i tce-load -i myextension to check if dependency are loaded and if my extension works. All was OK and works as expected.
So i edit bootlocal.sh, onboot.lst and filetool.sh -b to save config.
But, when i reboot, PI stuck on boot step "loading extensions..", with cursor rotating forever.
The only solution is to change bootcode adding "base" and manually remove my extension from /optional.
I checked permission and owner and can't find any strange.

Maybe someone could help me with some ideas?

Thanks!
Emanuele