Default [Q] How to disable USB host mode power saving?

Hi,

I've searched but can't find anything, hopefully I didn't miss anything.

I'm using the Zenithink ZT-280 C71 with official firmware 2.3.4. Since it doesn't have built in bluetooth, I'm using a Bluetooth dongle. It works fine except it seems to have a problem with the power saving function. After some earlier confusing results, I found that if I let the tablet sleep (whether after time or if I push the power button), the dongle light goes off. When I wakeup the tablet, the bluetooh dongle LED comes back on but Bluetooth no longer works. If I try to enable Bluetooth, it tries very briefly then gives up. If the Bluetooth is still working, I can enable or disable it and reenable and it's fine although I'm not sure how much it does. This doesn't happen if the tablet is plugged in, it's working fine hours later. So I'm pretty sure it's because the tablet disables USB power which unfortunately breaks the dongle requiring a restart to fix.

Is there any way to disable USB host mode power saving? Isn't good from a power saving perspective but then needing to restart I've looked in power control widget but nothing useful there, some setting in the build.prop perhaps? I've fooled around with hacking my LG Optimus P500 and another phone before so no problem changing files etc.

Alternatively I could try making the USB bluetooh dongle work with powersaving (although possibly this will be more device specific). I'm not sure but possibly the problem is related to the fact hotplugging doesn't work. If I start the tablet without the dongle and later plug it in, I similarly can't enable Bluetooth.

Any help much appreciated.