my ipad 2 won't start after 8.4 it just show the apple logo booting every 2 min

my ipad 2 was working excelent with 8.3, i put it to install 8.4 update pluged to charger , it downloaded the update and after apply, just show the apple logo booting every 2 min over and over.

i tried to recover, it show the usb wire and serial number in itunes, the logo and bar, say waiting for the ipad and return unknow error 9.

its the same in DFU mode.

tried in 3 pc with 3 originals wires. could be any solution or i had an ipad and now i have a brick ?