Apple has Blocked Restore with V 4.2.1
ERROR 3194 = The problem actually lies with the fact that Apple signs the firmware now and you cannot upgrade or downgrade an iPhone using a firmware that Apple has not signed anymore, so this issue might go away if you use an older firmware which is signed by Apple.
You can restore your 3Gs or 4G to 4.2.1 with custome firmware only if you have SHSH saved on CYDIA , if SHSH for 4.2.1 is not saved on CYDIA and you forced it with 4.2.1 your iphone Go to DFU mode and you can solve it only with upgrade to OS 4.3 > bad for jailbreak and unlock now .
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ERROR 3194 = The problem actually lies with the fact that Apple signs the firmware now and you cannot upgrade or downgrade an iPhone using a firmware that Apple has not signed anymore, so this issue might go away if you use an older firmware which is signed by Apple.
You can restore your 3Gs or 4G to 4.2.1 with custome firmware only if you have SHSH saved on CYDIA , if SHSH for 4.2.1 is not saved on CYDIA and you forced it with 4.2.1 your iphone Go to DFU mode and you can solve it only with upgrade to OS 4.3 > bad for jailbreak and unlock now .