After many shilly-shallying, I eventually released a new version of loaders-update that features the backup of the loaders, either the EFI and BIOS ones.
The BIOS loaders are just saved in
/root, but the EFI loader benefits from the possibilities that UEFI brings. The updated loader is saved in a way that you can boot on the previous one by simply call the boot menu at the starting of the machine. So, no need to boot on a USB key to mend the system in case of boot failure.
It wasn't not been without trouble, but I can propose this now, after numerous testings.
I keep that in the 'current' branch and not in the 'main', to let the time to discover if there are some critical problems. I'm mainly thinking to ARM64 arch, I can't test. I'm especially thinking to
dl8dtl who helped me in this way.
That said, anyone that will test and report here, or in the uploaders github, these new features will be of invaluable contribution.
A proof of concept concerning the automatic update of FreeBSD loaders - Emrion/uploaders
github.com