I wanted to upgrade to v.7.10 on my PB631/FW5.20, mainly to go around the 63Mb apparent partition containing a bit of this and a bit of that (probably similar to what reported by nhedgehog above), but ran in the following problems:
- Uninstalled the existing v6.3, replaced Jailbreak.app and Services.app; tried to run the newer Jailbreak.app, but that would report "Cannot install root" after several seconds
- Recopied Jailbreak.app of v.6.3, and jailbroke with that; replaced Services.app with the newest, ran that apparently successfully (e.g rooted menu under Settings), but then could neither ssh nor smb in after reboot. (ssh - connection on port 22 refused; smb - no mount point seen)
Reverted to v.6.3 for the time being.