Just one more or less minor addition to that - we (as in Purism) currently have no plans to get additional carrier approvals. Getting carrier approvals is a PITA and in most cases bound to very high restrictions on the device and a very expensive qualification process. Especially the restrictions carriers in many cases impose on handsets and their features or access of the carrier onto the handset (for remote configuration etc.) are “features” we do not want to have on our device. We want the users to have the maximum freedom on their device and not being forced to have locked down parts.
So if Sprint is not supporting our modem, I am sorry, the Sprint is not an option. In the US I know that e.g. T-Mobile is very open, in Europe it is the law that carriers must accept all 3GPP compliant devices.
Cheers
nicole