There's something preventing the v6 uninstall still :/
Try pasting the following into the shell, right after v6 uninstall, but before reboot:
Code:
chattr -i /mnt/secure/runonce/*
rm -f /mnt/secure/runonce/*
chattr -i /mnt/secure/init.d
rm -rf /mnt/secure/init.d
*then* reboot and try v8 install.
So what goes on? We need to make sure there's *nothing* from pbjb - init.d and files *inside* runonce folder must be gone after uninstalling, otherwise it will silently break next install, unless its a pbjb copy that uses the very same files that weren't removed.
v6 is fine with it because its their stuff. But v7 moved that folder into /mnt/secure/etc/init.d and if the old one (and its contents) remains, things will break horribly.