iPhone 3GS or 3G (software unlocked by redsn0w/ultrasn0w & similar) going from full signal strength bars to 1 bar to no bars, both 3G signal and wifi, to SEARCHING… to NO SERVICE, back to full bar signal strength, repeatedly, randomly especially with location services / GPS running (mouse pointer arrow visible in top right of iPhone screen) is because you’re using version 6.15.00 modem firmware (commonly called a baseband or BB) on your iPhone 3G/3GS.
Downgrade iPhone modem firmware to 05.13.04 to fix searching/no signal iPhone 3GS problems using redsn0w version 0.9.14b2 for OS X or Windows. Instructions and downloads are available from iPhone Dev Team:
– basic instructions on using redsn0w to downgrade modem firmware from 06.15.00 to 05.13.04
– updated instructions with 0.9.14b2 version of redsn0w.
6.15.00 modem firmware used for software unlocks of iPhones is meant for iPad, not iPhone. (Find your iPhone 3GS / 3G modem firmware version in Settings –> General –> About –> Modem Firmware (near bottom). Format is MM.mm.pp.
From my little experience with jailbreaking & software phone carrier unlock iPhones, using iPad modem software on an iPhone 3GS / 3G is not a good solution. Sure, your iPhone 3GS / 3G is unlocked, but your iPhone is barely operational, constantly dropping and searching for wireless signals during which the iPhone is useless especially when GPS / location services functions are running.
Leave a Reply