On my Quad 3.4.1, everything calibrates fine (except a compass issue of high offset no matter how I calibrate).
But on my HEX, 3.4.1 refuses to calibrate the accelerometers.
Also noted, when loading 3.4.1…I do not get the beginning “E. T. tones”.
I get what I would read as a fail - solid red light after a bunch of tones.
However, once I reboot the FC, it will then finish the reboot with the “E. T. tones”
Thanks for the report.
Accelerometers failing to calibrate is quite rare. I’d guess it’s a hardware issue but it’s hard to know unless we see a dataflash log. Maybe set LOG_DISARMED to “1”, try the calibration and post the log here.
For compass calibration, there was an issue with the onboard compass calibration never reporting it had finished. This is fixed in AC-3.4.2 which is out as the official release today.
3.3.3 Will calibrate on the HEX.
I will put that LOG_DISARMED on the list too for the weekend 
I had this same no cal issue back on 3.3.1…posted it…but it never got resolved!..had to go back to 3.2.x(?) workes fine have not even bothered trying newer ones yet
ptegler
Log files uploaded…