@mojo
I know it is possible to downgrade with the 107D, I have a 107D but I use one of Nils firmware hacks with that drive and it is reversable. I have not updated using one of the pioneer firmware updates so I cant say if it is possible to downgrade once using pioneers upgrader? I always use one created by 'Nil'.
I also have the 110D but have never upgraded the firmware for it as yet so I cant be 100% sure if its reversable for the 110?
Is DVRFlash still the tool to use? (Its been awhile since I update the 107 so am not sure if things have changed dramatically?)
If I were you I would consider trying what Joe suggested, that is try one of Nils firmware hacks.
And I hope you didnt misinterpret my 'Have you tried it' remark?
It was only meant to be a genuine question.
Good Luck
EDIT: Hmm it appears you may be out of luck! Just found this:
"Caution! Once the drives have been updated, the drive will NOT be able to be restored to an earlier firmware version."
I read that on
Pioneers site
So I now dont know if my 107 was reversable because it was a 107 or if it was because I used Nils upgrade and not the Pioneer one?