Gentlemen, I am having a hard time trying to jailbreak my 4.2.1 iPad. I'd appreciate some help. Basicly my device won't reboot after completing the 'Install Cydia' steps. Let me describe whole situation.

iPad 32GB wi-fi, model: MC821LL, running 4.2.1 (8C148)
device came with 3.x firmware, got it jailbroken, then before I saved my blobs I erased all settings and data through settings menu, which caused a brick, I had to restore to 4.2.1 through iTunes.

redsn0w 0.9.6b4 - Windows XP SP3, tried also on windows 7
iPhone3,1_4.2.1_8C148_Restore.ipsw

I am following all steps described in any tutorial available on the internet. Whole process seems to be going well, I get into DFU mode, redsn0w goes smoothly through all
phases, at the end it says 'Done!' and that resto of the process will take place on the device. Unfortunately my iPad won't turn on as supposed. Logo doesn't show up even for a second and device seems to be off. Device seems to be somehow stuck in DFU mode or just turned off, iTunes won't pick it up (even as a device in DFU mode), I can't 'boot tethered' as redns0w also doesn't see the device, I cannot even turn the iPad on the usual way. I need to play with different combinations of hold+home in order to boot it. There's obviously no Cydia icon after finally I manage to get it to turn on. I tried restoring my iPad and tried all steps again on a fresh iOS, even tried different operating systems, but situation repeats every time. Is there any known issue that could be causing this. What other steps can i try? I'd be very thankful for any advice.

ok, just to start simple.
-You charged it with ipad charger and it is charged.
-You have redsn0w on without the usb plugged into the PC...
then start the redsn0w app, plug in your iPad... follow steps holding power and Home, let go of power after 15 seconds, hang on to home button until it beeps and you see redsn0w running?

You may want to watch this guys video.
how-enter-get-out-dfu-mode-restore-mode-boot-loop-w-out-tinyumbrella-recboot

Thanks for the reply. It turns out I was using iPhone3,1_4.2.1_8C148_Restore.ipsw file instead of iPad1,1_4.2.1_8C148_Restore.ipsw. I feel a little embarassed that I didn't notice it. Thanks anyway.

i got the same problem, did u figure out the fix yet?
i downloaded the correct firmware iPad1,1_4.2.1_8C148_Restore
for my ipad 4.2.1 8c148.
after the install, redsnow waits for ipad to reboot, but the ipad doesn't reboot. and cydia isn't installed.

Originally Posted by euromp

Gentlemen, I am having a hard time trying to jailbreak my 4.2.1 iPad. I'd appreciate some help. Basicly my device won't reboot after completing the 'Install Cydia' steps. Let me describe whole situation.

iPad 32GB wi-fi, model: MC821LL, running 4.2.1 (8C148)
device came with 3.x firmware, got it jailbroken, then before I saved my blobs I erased all settings and data through settings menu, which caused a brick, I had to restore to 4.2.1 through iTunes.

redsn0w 0.9.6b4 - Windows XP SP3, tried also on windows 7
iPhone3,1_4.2.1_8C148_Restore.ipsw

I am following all steps described in any tutorial available on the internet. Whole process seems to be going well, I get into DFU mode, redsn0w goes smoothly through all
phases, at the end it says 'Done!' and that resto of the process will take place on the device. Unfortunately my iPad won't turn on as supposed. Logo doesn't show up even for a second and device seems to be off. Device seems to be somehow stuck in DFU mode or just turned off, iTunes won't pick it up (even as a device in DFU mode), I can't 'boot tethered' as redns0w also doesn't see the device, I cannot even turn the iPad on the usual way. I need to play with different combinations of hold+home in order to boot it. There's obviously no Cydia icon after finally I manage to get it to turn on. I tried restoring my iPad and tried all steps again on a fresh iOS, even tried different operating systems, but situation repeats every time. Is there any known issue that could be causing this. What other steps can i try? I'd be very thankful for any advice.