To debrand you need : Downloads - R8BA024_RED52 - Top Sony Forums

W610_R8BA024_FS_EUROPE_2_RED52
W610_R8BA024_MAIN_GENERIC_NA_RED52

EUROPE_2 , 3 or 4 can see in service menu. When keypad is unlocked click:

> * < < * < *

Service info > Info software

CDA...
cxc
and here is you region : may be Europe_2 , 3 or 4

and download: Downloads - w610custpack - Top Sony Forums