Just noticed that a new firmare is available from AVM: FRITZ.Box_Fon_WLAN_7390.en-de-es-it-fr.84.05.21.image
And while on the FTP server, I also noticed a new source package: fritz_box_fon_wlan_7390_source_files.05.20.tar.gz
The good news is that judging by the size alone, (951.247 KB) there...