I've got an iPhone 4 that I just updated to 4.3.1 and jailbroke. I'm trying to preserve 1.59.00 bb, which seems to have been successful.
I have the one bar issue--I haven't seen confirmation that this is just cosmetic. My gut says it is more than cosmetic because my data rates seem slow, but that could be a lot of things.
In any case, you can see where this is going. I installed ultrasn0wfrom cydia. After seeing this thread, checked MMS, and sending them seems to silently fail. Just asked someone to send me one to check inbound, and I haven't gotten anything yet.
So, I removed ultrasn0w. Still no MMS. Removed TetherMe as well, since it has APN settings. Still nothing.
Various combinations of reboot/power off/eject SIM/reset network settings. Still nothing.
I'm starting to think I'm going to have to restore, and honestly, I'm thinking along the same lines as the poster above. With a real unlock, whatever the premium, preserving the bb doesn't make nearly as much sense anymore, so I'll probably upgrade the bb this time.
Anyone else have this problem after completely removing ultrasn0w? I'm stumped.
ETA: After a bit more testing, it is my MMS *receive* that is broken. Send is OK. But, since receive is broken, I can't test by sending to myself.