Cant load ac3.5.7

For a week ago I uppgraded to latest firmware, ac 3.6.2 and Chibios and my troubles begin…
I got “Initialising APM” as massage and was not enable to calibrate esc,s.
I had made more than 200 flights with same Pixhawk “knok off” 2.4.8 0030001B 32365114 37353639
1e7ed30b NuttX: 1472b16c firmware 3.5.7 without any major issues.
I can roll back to ac 3.5.5 but not ac 3.5.7. When I choose previous firmware, ac3.5.7 quad and do uppload I got 3.6.2 ??.
I tested to load it several times, allso tested to load plane and back to quad.

Regards YJB