I use US iphone 4 in the UK with Orange. it has 01.59.00 baseband jailbroken with Pwnage tool an unlocked with ultrasnow. If I use it with 4.2.1 custom firmware activated with my old AT&T sim, then after the unlock and insertion of Orange sim I get message "iphone activated" and everything works perfectly well, except that every few days the signal will be lost and "invalid sim" message pop ups. This can be solved by rebooting.

I week ago I changed to 4.3.3 custom firmware. I never got "Iphone activated" message and quite often when I use cellular internet I get "could not activate network data" message. It seems that ultrasnow is more stable on this firmware - never had "invalid sim" message. I also tried 4.3.3 with hacktivation, followed by SAM activation. This seems to make the network data working more stable, but I lost MMS.

Is there a way to get a proper activation from Orange on 4.3.3 and still have my MMS working?