how to reproduce
start fcamera
enable blink led on capture or without it at times
take a picture 
after that keyboard and indicator lights fail 
reboot dosent help

reproduceablity 
4 out of 5 times i dared to try after a full reflash

more context to the issue as pointed out by esteemed electronics engineer Joerg Reisenweber

\"fcam is known to have a nasty bug of writing to LP5523 indicator/kbd-backlight controller chip directly via I2C
and causing massive messup at times to the chips. AFAIK this never got fixed and only can recover from it by removing
battery and unplugging charger for several minutes until LP5523 and possibly other chips on same I2C bus too finally
reset to a sane state

BR
jOERG  \"