i had the same issue with mms on tp2 with boost.. Fixed it with a simple cab file look for arcsoft_mms_5_2_6_45u.cab that will enable u to edit the address for the mms to the boost one which is
http://mm.myboostmobile.com in the options in text messaging. and you should be able to receive and send mms. As for the flashing question, you dont need to get it flashed there is a work around for it thru the sprint.com website. If you need more details dont hesitate to ask.. kinda flew thru it since im at work..