Root [Boost Mobile] Unflash if there is such a thing

[130ft]

New user here with a question for all the experienced flashers.
Bought a sprint S3 flashed to Boost prior to boost offering the phone. Is there a way to unflash or reset the phone to stock configuration and than bring it over to boost as an S3?

My reasons would be the donor phone (Boost clamshell) is 3g max and the updates don't work. Also some of my text sent via xxx@myboostmobile.net are not downloading.

Any suggestions would help. I have 2 family members on the same set up so 3 phones in total.

Thanks

 

[jstoner]

Not sure about unflash maybe a restore factory reset not sure but for text get go sms can send receive text and pic mail vs stock messaging app

 

[zzgtp99]

Ive used several flashed phones,doing the factory reset might remove the flash,but if it was done properly it wouldnt change the esn,and no Boost wont activate it,it would show up as a Sprint phone.