MotoCache's root doesn't care what OS version you are on...No need to update.
That's why it says regardless of OS version...
Edit: The update.zip you are flashing isn't a ROM. It is only the things necessary to make the stock ROM you are on, rooted.
If you want to flash an ROM, you just need to find a stock one. Peter has one, MetiCkOne has one and Gimp Project has one.
http://www.droidforums.net/forum/metickone/104030-rooted-stock-odexed-deodexed-frg83d.html This one is not FRG83G, its FRG83D.
http://www.droidforums.net/forum/pr...77-rom-frg83g-gimpm0d-modded-stock-avail.html FRG83G Stock is the second link. This is based off of PA's stock.
Deodexed is theme ready.
Odexed is stock signed files, so no theming.
Thanks! That really explained a lot!
Following your 'Flashing a ROM on a Droid 1 - Best Practices' I used the odexed rom from Peter and it flashed easily from SPRecovery.