在爬文後被搞得好亂所以乾脆發一篇求救文小弟的舊美板iPhone 3G本來韌體3.1.2用得好好因為自以為是沒做好功課的想要升到4.2.1後來發現要更新出現"No sim card installedinsert a valid sim with no pin lockto activate iphone"的字樣然後就甚麼都不能做了有誰可以救救我啊!!
An alternative option is to create a custom firmware with PwnageTool and upgrade to baseband to 06.15.00, then unlock with ultrasn0w.However, you will lose your GPS functionality once you do so and you can *never* restore to stock iOS anymore.