Ipad 2 stuck on 75% of restoring

Hi everybody

When i try to restore my ipad 2(it's in recovery mode) with itunes 10.6 to the current iOs 5.1 it's stuck at around 75% of the progress bar on the ipad screen. I tried it 98897768x times on my imac and MBP and with different cables.

I can't get the ipad in DFU, only recovery mode. I think it's a hardware problem, so if it's, what could it be ?

Thank you !