Downgrade bepop2 from beta 4.0.0 to stable

I have installed arducopter 4.0.0-dev to my bepop 2 with mission planner custom firmware installation function. I had some crash due to sudden deviation from route in auto mode. I wan’t to try with stable version of arducopter-quad (3.4.6). Anyone can help me to downgrade arducopter? The install custom firmware function of mission planner doesn’t work with arducopter 4 installed in the bepop2…

have you try to download the firmware @ http://firmware.ardupilot.org/Copter/
use “Load custome Firmware” in MP?

Yes, in the past I installed the firmware 4.0.0 (latest version) to the bepop 2 with MP, and everything worked. I tried to install the stable firmware (to replace the beta version) in the bepop 2 with MP, but when MP try to connect to the bepop 2, after asking me to connect to the drone wi-fi and after the Linux and bepop 2 question dialogs, MP hungs and don’t show the “press four times the power button” dialog… I supposed that the problem was the presence of the arducopter firmware in the drone, so I long pressed the power button for ten seconds… the bepop was restored to factory setting… but the MP behavior didn’t change…

unfortunatly i dont have a bepop2 here for testing. Does the Bepop2 normaly also communicate with the QGroundcontrol? Sometimes I had Problems to load Firmware with the Mission Planner and with the QGC it works. And sometimes vice versa.