N95 - random resets after firmware update. hw or sw?

Hi all.

I've just updated the firmware on my classic N95 and now am having problems with it. It now seemlingly randomly reboots itself. It doesnt freeze, just all of a sudden the screen goes black and then flicks back to white background with blue nokia logo in the middle and then the phone boots up normally. The key pad lights or screen back light do not go off when it does this.

The phone was fine prior to the firmware upgrade.

My first thought was that it was related to the data I had restored back to it (only contacts, messages, etc) so did a reset (*, 3, Green) and then did not restore my backups onto it. No change, still the same.

If i leave the phone alone, it does not (as far as i can tell) reboot itself. It only seems to happen when i'm using the phone as i press a button. There is no pattern to which button triggers the reset.

I have been trying to work out what might be causing, have taken the memory card out to eliminate that - no change. Disabled UMTS, no change. Disabled keypad tones, no change.

I'm not really sure where else to look, because to me it seems like a hardware fault but this phone has been flawless for nearly 12months before upgrading the firmware.

Any help greatly appericated. I think i've included as much info as needed, but if i've missed something let me know. My carrier is Vodafone, UK.

V 21.0.0.16
14-02-08
RM-159
Nokia N95 (01.01)

I have since tried *#7370# and also reflashing the phone using NSU. It didn't redownload the file, but i assume it performs CRC checks before flashing.