Revert bootloader ph 2.1

After some test on 4.0.3 arducopter i have try to upgrade bootloader of ph 2.1 to chibios , now i need to rollback to nuttx , there is a way to do this ?

Thanks to all

Why do you specifically need NuttX?

Because i need to rollback to 3.5.7 and is not possible with flashed bootloader

But why that version. There are multiple serious issues with older versions that should not be ignored. You really should be using 3.6.12 or later for copter or 3.9.11 for plane.

I know all new fixes, but i have well tuned on 3.5.7 and orrible with 4.0.3 i’m not sure all param will be scaled well

It is unsafe to run on 3.5.7

Please do some research on Ardupilot to find your issues

Thanks @philip is safe to use pid param of 3.5.7 and use 3.6.12 ? I will recalibrate Compasses and accels also

Nothing with the PID controllers has changed in 6 years or so. There are some small changes coming in the future with filtering for copters, but that should still not change PID values greatly.

Do not use any firmware before the current release.

Find your problem, and fix it.

Helping you put bad firmware on your vehicle would be advising you how to crash