I never said it did, I said check to see if it's possible before trying it.
But the real problem is that I spaced that T-Mobile is shutting down the CDMA network.
If you're trying to go from CDMA to GSM, pretty sure you can't.
First problem is that the CDMA G3 uses a UICC for LTE access - the GSM model has a what that service needs - an actual sim card.
Second problem is radio hardware.
So, I don't think that this is a flashing issue.