you can flash it to K810 with FAR manager but you can't apply patches on it

you will need K810 R8B003 MAIN, FS and the CDA file for your regio

FS and MAIn are here: Downloads - R8BF003_RED53 - Top Sony Forums

CDA is here: Downloads - k810custpack - Top Sony Forums (choose the right one for your regio)

i made a little guide on how to flash the firmwares and it includes a download link for the full FAR+JDflasher package. link: FAR + JDflasher - Top Sony Forums

oh yeah you might want acces to the download area. more info here: Request access to Download Area - Top Sony Forums