Even if sim-unlocked and firm-updated, the connections to NTT Docomo of
my softbank 007z are not stable. According to
2ch, a softbank 007z supports Band9 (1.7GHz) and Band11 (1.5GHz) only, Band1 (2.1GHz) is not supported. It also imformed that the modified
007z for BIZ firmware makes it possible to catch Band1 in exchange for unsupporting Bnad9 and Bnad11.
Change "SBMFAREN_JP_MF80" to "SBM_JP_MF80V1.0." by Binary editor and flash.
The connection to NTT Dococmo becomes very stable. However, this is not recommended, as it is said that the restoration to original firmware is impossible.
007z in USA