Had the same issue with the download stopping at 24%. Reason is that DJI has corrupted firmware on some of their servers. If you are out of luck, you‘ll receive the corrupt files from one of their affected servers and the md5 hash check fails for a specific file of the firmware. The only solution for me was to get myself a VPN and do the update via a different server location. Even after my update went through this way, I got an ‘inconsistent firmware’ error message in the app. The app then did some fixes and so far so good. It’s not very reassuring, though, failed md5 checks and the error messages make me a bit nervous about this bird...