Microsoft is the US military's biggest supplier. There is definitely a solution for this. And that solution is probably not available to regular users.
1. Supply the code given by the "slmgr /dti" command to Microsoft over the phone or online from a non-air gapped machine.
2. Apply the resulting activation code with the "slmgr /atp" command.
Even in Enterprise by the way. No way we pay the amounts listed on the MS website.