Wubi upgrade to maverick beta fails to boot

[bcbc]

Installation of 10.04.1 with all current updates. Upgraded to maverick, during which I selected to install grub to the /dev/sda device (to duplicate what many users did during the 10.04.1 updates). After the upgrade I confirmed that grub had installed to the MBR pointing to partition #256 as expected (as the wubi install was to a partition other than windows). After fixing the MBR, the wubi install failed to boot.

Grub reports:
Error: unknown command: loadfont
Error: unknown command: gfxterm
...
Error: file not found

Computer then reboots.

Additonal info:
wubi installed to partition on external drive /dev/sdb8 (type fat32) 5GB root.disk

I've rerun the upgrade since without doing the grub test and could not duplicate the failure. In each upgrade (one on the same partition as windows, one on a different partition) the upgrade was successful.

[bcbc (bcbc)]

Reran same upgrade method with a fresh install of 10.04.1 (updated) on a different computer, this time on the same partition as windows and it worked fine.

I'll rerun the different partition install to try and confirm the problem.

[bcbc (bcbc)]

Reran initial upgrade method without additional grub test (as described in updated description). No problems encountered. I will run a new test to see if I can duplicate the initial problem.

[bcbc (bcbc)]

I can't duplicate this - therefore I am marking it invalid.