Hi Guys,
after software update my stb is resulting no more bootable. I've also tried the upgrade from bios combo, by holding the OK or MENU buttons at boot but nothing to do. The device is in infinite loop in which it starts, loads os and then reboots.
Following the output of serial console through sequents boots:

MC: APP init ok
<< SDK4.0ba.4.2_20110225 >>

Libcore version 7.5.0@SDK4.0ba.7.5_20120322(gcc (7.5.0@SDK4.0ba.7.5_20120322(gcc) version 3.4.4 mipssde-6.06.01-20070420)(vic.wang@ Tue Mar 20 17:52:46 2012)

Application version 1.0.0@SDK4.0ba.7.5_SAB_S2_20120322bymicozhang (1.0.0@SDK4.0ba.7.5_SAB_S2_20120322bymicozhang)

James try 2
USBD->Error :Bus rst OK!
USBD->Error :Bus rst OK!

Thank you in advance for your support.