you can follow the official instructions, just replace the hex file with the new one.
re: the latest beta - normally it will be in the official beta thread: https://llllllll.co/t/teletype-2-3-release-beta-2/11232
however, we had a recent scare where it appeared a teletype was damaged by directly plugging grid into it. teletype is not able to provide enough power to grids, grid must be powered externally. tehn was investigating and it looks like it was an unrelated issue, but until it’s officially confirmed my plan was to modify the firmware so that when a grid is connected it would ask a user to confirm it’s powered externally. i removed the posted beta until i can post a new version with the confirmation included (or until we know for sure there is no danger to teletype if you plug a grid directly by mistake). if you would like to try the firmware now just PM me and i’ll send you a donwload link.
3D2CCB9 is indeed the latest beta posted - i’m hoping to have a final beta posted in 2-3 weeks.