I just updated my rover to the new RT raspbian image and the newest APMrover.elf.
I used a new SD card, so I can keep everything on the other one.
I saved the APM settings and loaded them to the new installation with MissionPlanner.
Everything is working, except for the camera gimbal output.
I have connected the servos to PWM outputs 5 and 6.
In MissionPlanner, outputs 5 and 6 show 0us.
I changed one servo to output 4 and set it up as gimbal_pan and as soon as I saved it, output 4 also showed 0us in MissionPlanner.
Setting outputs 5 and 6 to passthrough gets the servos working again, but without any stabilisation of course.