If you don't want to order a Torx screwdriver...
Kobalt makes an awesome 8 in 1 screwdriver that has 8 different sizes starting with T4 and it's available at Lowe's for sure. Found mine in 2 seconds in the screwdriver section. I'm posting this because I've seen so many people asking where to get them, and a few saying that the geniuses that work at Lowe's/Home Depot couldn't help. And personally I didn't feel like ordering one one online and waiting for it to get here, so I went looking for myself. Low and behold there it was! and not just the T6 I needed but an awesome little tool that had all the sizes I might ever need for phone mods!