It would not work because of the bands on the phone which can not be modified. From what I understand, Xiaomi M1's bands are 850/1900/2100 Mhz for 3G and T-Mobile's bands are 900/1700/2100 Mhz for their 3G.
I have trouble with the Browser on the N1 too. I have to clear the history and cache to make it function again. I like the stock browser more than the new one. ><