How can I upgrade the CAnopy OS without using CNUT

I have several SM’s using Canopy OS version 6.1 and earlier. These units are not on the active network. Is there anyway I can manually upgrade the OS on these units with out using CNUT, using Telent instead?

I have a laptop that has 2.x and 3.x and I just connect each radio and upgrade them to 7.3.6 using CNUT2, then use CNUT3 to upgrade to 9.3