I would not recommend. Even if you dare to try cross-flash it, I would suggest you to experiment with the the v3.80 data package first. If anything goes wrong, you can at least try to go back with the T-Mo one. Also, I would try to compare the file sizes of BOTH variants' MCU files. If they are the same, I rather just flash the PPM and image and leave the MCU alone because ou never know if it will screw up the RF tunings.
HC - NO "i"
I am NOT "the" HC, we are TWO different individuals!
"If we amplify everything, we hear nothing!" - Jon Stewart, Comedian