OK I gave up on workshop because my Prevail refused to answer workshop.
Right comport but the phone just won't talk to workshop.
Here is how you get your MSL from the Boost Prevail.
First download oneclick root and install. This part you do from your computer's desktop
Second down load the Superuser app and install.
Now down load a app called connectbot and install.
Here is a web page to help.
Your have to add your on Http to the above link as I'm a new user and the site won't let me
Make sure you use the first command "su" for superuser (answer yes) then on the next line
type "getprop ril.MSL" no quotes
You will now have your 6 digit msl
I hope this helps someone else
EDIT: use ##8778# and then enter your MSL number now another screen pops up and you are in the DM mode on the Prevail change it to USB and go back to workshop and it should now work.