Format the sd card on your P3S then copy the firmware bin to it, then turn your radio on open dgi app select top right corner more than 3 seconds to apear firmware downgrade then select and done. :)
DGI app fail 3 times when upgrading to the latest firmware 1.8.10. After that its all ok no test flight yet. If anything bad we can always downgrade »» format sd card from the bird than copy the bin file to it, download it from DJI Phantom Accessories & Tips - Phantom Help.