We have a speedybee f4 v4 and when on fully charged batteries. it arms and flies perfectly every time. but if we start with a battery that is about 70% capacity left it takes ages to be able to arm and only one or two motors would spin up, and then you give the drone a bit of a jiggle and the others wake up, then you can fly. very strange.
it sometimes gives a failsafe during prearm, a internal error 0x4000 1:215 spi_fail
i think we on 4.5.6 i forgot. the drone is with my dad so i cant just check it out. Trying to help him figure it out.
Ant ideas what could cause such behavior?