Downgrade to DOPOD 1.0 ROM for CID unlocking?

[coolfire74]

Hi, guys, I found this ROM (RUU_Prophet_1001321_10013102_11320_DopodAsia_Ship .exe) from XDA FTP (/Prophet/Shipped_Complete_Updates/Dopod/DopodAsia Official ROM Patch Driver/Dopod 8181pro ROM). What is this ROM exactly? Is there anyway to downgrade from JAMin 2.13 ROM to this DOPOD 1.0 ROM? Since the CID unlock can only be done with 1.XXX ROM, I really would like to install this 1.0 ROM for this purpose.

Thanks a lot!