Your 6-Axis Robotic Arm's firmware can be updated within VEXcode EXP. To do so, make sure you have first powered on your 6-Axis Arm, directly connected the 6-Axis Arm to your computer, and connected the 6-Axis Arm to VEXcode EXP.
On VEXcode EXP, after you have started a new Arm project, the application will detect if the connected 6-Axis Arm's firmware is up to date or not. If it is out of date, a window will pop up.
Select Update.
Wait for the progress bar to finish. Make sure to not click off the current webpage until the update is over.
Select OK.
The 6-Axis Arm will be automatically reconnected to VEXcode EXP.