@RangerZ:

Can you confirm that the EC25-A is for both T-Mobile AND AT&T? The spec sheet from Quectel lists only B2/B4/B12, so it appears to be missing B5/B17 for AT&T. However, B17 is AT&T’smost common band, so I cannot imagine they could list this modem as AT&T compatible without B17.

@alzhao

What is the possibility of using Sierra MC7455 cards in Mifi? I know that they are very expensive for a hobbyist, but they have the best support of carriers and can be switched whenever you want without changing the modem. It seems that these modems are supported in R00ter build of OpenWRT as well as several GL.Inet routers, but not MiFi.