If commenting out the spytask does not help, comment out the kbd task also and start the original kbd-task instead.
I dont know how the S90 works, but on the G11 i had to change the "usual" code in kbd.c,
because with the standard implementation, display&key lightning are switched off and the camera "looks" dead/off, but it wasnt.
Also disable all chdk hook tasks (capture, movie, etc.). There are not so important now, chdk will run also without them.
You can activate them later, after you are sure that spytask and kbd task are running stable.
Another pitfall, which often crashes the g11 during startup, was the spytask config loading. If fixed that in the G11 port. I expect that you also need the other chdk core changes for the new dryos, so maybe you also have to set the CAM_DRYOS_2_3_R39 define in camera.h. For that, you need the actual chdk code (with g11 port included).
