Okay so you’ve upgraded to Apple iPhone 2.30, but want your iPhone unlocked but now find out that yellowsn0w can’t unlock iPhone 2.30, so what can you do?
Well you can now downgrade from iPhone 2.30 to iPhone 2.28 which will work with yellowsn0w says a report over at gadgetlite. This is achieved by an iPhone 3G baseband firmware downgrade utility know as “pHasebandowngrader.”
However, the “pHasebandowngrader” utility will only work if your Apple iPhone is running bootloader 5.80. If so then you should be able to downgrade your Apple iPhone from 2.30 to the more unlock friendly 2.28 firmware.