Yes - it's true - tested by me a month ago ... on brand new PCB from 6300b i was take out RAP and Flash IC, just placed in RAP and Flash from ordinary 6300 - all working fine - there nothing to do with RF hardware ... so can be thinked in 2 ways - 1-st: RAP is factory locked to 850 MHz ( this can be checked if you have good working RPL file or IMEI backup from 6300 phone.... just take out his RAP and put to 6300b without to change Flash IC, write 308 PM to avoid locking ... try to catch network - if phone can make a calls then RAP is a key... for sure there phone will be with fu.cked IMEI and will shut down on 30 min, but this is just experiment ... everytime you can rebuild it with your RPL or IMEI backup ) - 2-nd: There after RAP change - still no network - then revrite flash IC content step by step with IMEI backup - first certificate and PM308, check network, after this, PM309 - check network, after this - PM1 - check network ... if still no network, then the key to achieve band convert is somewhere in other PM fields... ( but i don't think so ).
WBR, DebeliaMark, BG