Well I went ahead and tried out the 136.218 firmware. No issues with sound so far, however I have a major new issue, in that the screen is blank when coming out of standby!
I get audio (e.g., if pressing TV guide + ok to switch to TV), but nothing on the screen. I've tried a few things, such as casting, etc , to see if that causes the screen to turn back on, but no joy.
So I now either need to downgrade (which k assume is not easy), or turn the TV off at the plug each time to reboot it.
Has anybody else experienced this? Any suggested fixes? Thanks