This happens on the MI1, but did also happen on the Huawei Honor I used before. It does NOT happen on the MIUI Germany version. My carrier is O2. All Roms I ever used show this (Usually they show "O2-de", as I am in Germany). The MIUI Version from http://miui-germany.de/wp/ also does this correctly. The version from miuiandroid.com however shows "Tchibo". That is a brand of coffee shops here, and it seems they also resell some mobile phone contracts from O2, but my contract/SIMCard has nothing to do with them. I already googled, that it seems i could hack some resource file or some such to "fix" this, but it would be nice if this mapping could be repaired for everyone. I'd be happy to provide the necessary information, if you tell me what you need.