Upgrading to Froyo


My Acer Liquid E has the current ROM for the Pacific region, but what is unusual is the ROM itself : Acer_LiquidE_2.100.27_EMEA_CUS1

I know right! EMEA! What!

Anyhoot, I'm trying to figure out how to get Froyo 2.2 on it without bricking it. Does the ROM need to specifically stay at CUS1 or can another ROM replace it (without rooting), outside of CUS1? For example upgrading to the 4.xxx.xx ROMs.

Now I know there has to be someone out there, that has already done this. So throw us a bone will ya.