Dont know if roms all also band related..
Nokia Lumia 800 variants
RM-801 / 800 - Global - GSM 850/900/1800/1900 MHz, WCDMA (3G) Band I (2100), Band II (1900), Band VIII (900)
RM-819 / 800.1 - US - GSM 850/900/1800/1900 MHz, WCDMA (3G) Band I (2100), Band II (1900), Band V (850)
Well if...