Ok man,
1. About ADFU: Copy AdfuUpdate.inf somewhere as a backup and then change it as u say. Honestly I HAVE NO IDEA WHAT THE HELL IT DOES, but if you believe it, u can try it. But make a BACKUP. As you say in your instruction i would do:
Device Instance Id
USB\VID_10D6&PID_FF66\5&1BBE8508&0&8
Hardware Ids
USBVID_10D6&PID_FF66&REV_0100
USB\VID_10D6&PID_FF66*
I really know nothing about this, so i am sorry
2.Mp4 Uttilities
Tell me ! Are you able to upload firmware by your utilities ? What exactly it says when u try it ?
Also you can try the Product tool Uttilities 4.19 found here:
http://s1mp3.org/files/3rdpary_softw..._Toolsv4.19.7z
Good luck