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Posts tagged Dev-Team
iPhone Dev-Team Offers Tips to Fix Unlock Issues
Jul 20th
The iPhone Dev-Team has posted some tips to help those experiencing problems with the UltraSn0w unlock
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It looks like version 0.9 of ultrasn0w fixed up the vast majority of any problems people were seeing with the 3G/3GS carrier unlock. But here’s a brief list of fixes for anyone still seeing problems:
* Unusual battery depletion is almost always caused by people choosing to “Restore from backup” instead of “Setup as new iPhone” when iTunes asks you. This isn’t caused by either the jailbreak or the unlock, but it’s a common 3.0 snafu. The fix is to just re-run the official 3.0 restore and choose “Setup as new” this time. Your music and apps and all that will still be synced, but you’ll get rid of any conflicting wifi, bluetooth, or carrier settings. Then just re-run redsn0w and install ultrasn0w.
* Remember, ultrasn0w works with hacktivated phones too, but don’t outsmart redsn0w into thinking you don’t need hacktivation! If you don’t plan on using an official sim, don’t activate via iTunes with such a sim. Just keep your unofficial sim at all times and let redsn0w and ultrasn0w handle hacktivation 
* T-Mobile in the USA doesn’t use the 3G frequencies that the iPhones support, so turn off 3G in Settings->General->Network. (Some T-Mobile territories gracefully hand down to Edge mode, but most do not).
* Certain unofficial plans have limitations on whether you can make calls and use data at the same time. That’s not unlock-related.
* Some people have installed previous versions of ultrasn0w using non-standard techniques. While the ultrasn0w 0.9 update should have removed all previous versions of ultrasn0w, these users may have outsmarted our removal. So make sure you don’t still see /usr/bin/ultrasn0w present if you’re at ultrasn0w 0.9 (which doesn’t have such a binary anymore).
* If you don’t need or plan to update to ultrasn0w 0.9 from a previous version, you can avoid having that red badge over Cydia by removing repo666 as a Cydia source. Don’t worry, you can always add it back later If you follow us on twitter you’ll be advised of any new updates anyway.
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We’ve found he had come up with some pretty neat ideas, including patching the actual text of the baseband code by copying it over to RAM and then using the MMU and page tables to have the baseband pretend it is part of the original bootrom. Of course, like yellowsn0w and ultrasn0w, this code has to be reloaded with every reboot of the baseband. However, the advantage of this is that developing unlocking payloads is a lot simpler… in fact, geohot used the same payload in AnySim and BootNeuter. We kicked around this idea ourselves before, but eventually found a work-around for the same problem with the yellowsn0w/ultrasn0w payload. The two pieces of code have the exact same effect on the baseband… with the difference that geohot’s exploit overwrites an arbitrary block of memory one megabyte in size. The baseband has a total of eight megabytes of memory and every bit of it is earmarked for use (except for 485212 bytes of it which we haven’t accounted for yet, but that’s still less than 1 MB). This means that eventually the area of memory geohot is using will be corrupted and 1 MB of baseband code will be corrupted (until the next reboot). How soon will this happen? Will it even matter in day-to-day use? We don’t know, because we haven’t spent much time looking. However, why take the risk when the yellowsn0w/ultrasn0w payload accomplishes the same job with no corruption?
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