You are correct, you will need a Russian Rom, I had to go through the same thing with my Dell Axim X51v, it came as Portuguese and I needed to change it to English.
I had to find the correct Rom with a specific date, which I believe was the same date or version as the Portuguese one that was on it, fried a couple of Axims learning the correct process to change them into English.
ASUS Maximus V Gene MB
Windows 8 X64; Windows 7 X64; Windows 7 X86
16GB Corsair Vengeance Ram
eVGA GeForce GTX 550 TI
Corsair GS700 PS
1TB Seagate SATA 6.0Gb HD