PVR (TVheadend and VDR) unusable on Raspberry Pi 1

Hi,

on my Krypton test installation I found following issue:

PVR live stream and recordings does not start on a Raspberry Pi 1:

1) After starting a live channel, the rotating circle in middle of screen appears for some moments and than returns to screen I have seen before but nothing happens

2) I can see in bottom left corner of screen the Full screen button and on the middle the channel played, but nothing will be played

3) What I have to do is entering Full screen manually and sometimes PVR live or recording starts, but mostly it does not. After pausing and unpausing finally it starts

I’ve been played with different PVR settings and using OMX Player or MMAL, does not make any difference.

1)2)3) During this states system is completely busy (Kodi requires all CPU)

Debug log: see here

Any hints?

Oh, I forgot:Raspberry Pi 2 and 3 are ok (same version pre-Beta3 running on XBian)