YEP! DOWNGRADE FROM T-MOBILE 1.72.00 to 1.66.00 IS POSSIBLE!

[kaimano]

:D YEAH! :D
I am successful in the enterprise! 8) In order to make the downgrade enough to remove through eredit the Device-Type and the Language, being only left the name of the operator. Now I have newly the rom Italian!
:shock:
P.S. About Device-Type, in my device now, the Model N. it's appears as PH10B.. I remembered it without the final B, only PH10... it's right? :?:

[jakert]

Hello,
may you please post how you downgrade the XDAII from 1.72 to 1.66?
I want to downgrade, too, but always get Model ID or Country ID error :(

[kaimano]

Of Course... remove through Eredit
the Device-Type
and the Language,
and be left the name of the operator that you used before the downgrade.

[sider]

I also managed to downgrade back from ROM 1.72 to the 1.6 ROM
Though that seemed impossible on my friends unit since it came with bootloader 1.06 while mine came with bootlaoder 1.01

When I tried it on my friends unit, it was left suspended in the bootloader screen. And ultimately we had to send it back on warranty.
So before you try it, don't do the same mistake we did, and backup your ROM first on an SD card. Just to be on the safe side.

One thing I noticed after downgrading is that the Ext ROM version is still 1.72. Is that the same thing with you kaimano?

Good luck :)