i found a way to get rid of that 0x0004 Rsd error this does not require any special cable just the normal one
1:Type "Fastboot oem unlock" and Enter: It will say "Waiting for device"
3: Immediately press'n hold "Vol- and power", when the Dual core logo appears. You will need to hold them down for 10-20 sec
2:Reset the Xoom (Power and Vol+)
4: After 10-20 sec you will see that the fastboot command gets through and you can unlock the xoom with fastboot oem unlock (MZ604 US)
1:Type "Fastboot oem unlock" and Enter: It will say "Waiting for device"
3: Immediately press'n hold "Vol- and power", when the Dual core logo appears. You will need to hold them down for 10-20 sec
2:Reset the Xoom (Power and Vol+)
4: After 10-20 sec you will see that the fastboot command gets through and you can unlock the xoom with fastboot oem unlock (MZ604 US)
