Knowing Sprint won't work with a custom ROM or an unlocked bootloader, I used the "flash-all.sh" script over here: developers.google.com/android/nexus/images#mysidspr
to restore the phone to stock, and then locked the bootloader. ADB and Fastboot were already installed.
I brought the phone to Sprint, and the technician took a look at it. The tech claimed that I had managed to wipe my RTN and MSID, showing me a screen with a clearly deleted RTN and MSID. Furthermore, the tech claimed that it apparently would cost me $75 for him to put a new one on my device, which is frankly ridiculous for a data transfer of a couple kilobytes which will probably take two minutes.
Not to mention, unless Cyanogenmod is some sort of trojan that will wipe your device's RTN after 6 months of use (unlikely), the RTN wipe was caused by my reversion to stock and is unrelated to the original cause of my cell radio not working.
What sorts of options do I have? Is there a way to get my device working that will not cost me $75 (which I'm certainly not paying as I'm off contract and could get a new phone on the cheap)?
Unfortunately, I do not have a backup of my working phone- there was nothing on it which I cared about, and had no problems wiping all data.
I did find a number of other threads regarding the IMEI, such as this: http://forum.xda-developers.com/gala...lease-t2497746
Unfortunately, I definitely do not have the original EFS folder.