This is an update based on reports from 25.10-BETA.1
An issue has been found on upgrade blocking some systems from upgrading.
Currently in 25.10 GRUB is being updated during upgrades if a version difference is detected between the current and new GRUB. However, the code expects a BIOS partition to already be present, so if an environment doesn’t have a BIOS partition, it will throw a traceback. Systems initially deployed with TrueNAS SCALE will have this partition, but some systems originally deployed with TrueNAS CORE may be impacted.