What does the reset button do?
The reset button is hardwired to cut all power to the system instantly and does not allow muOS to safely close anything currently running. This is like pulling the plug from your PC while it is still running, and is likely to cause corruption of important files.
This may not become apparent until much later when your device starts exhibiting weird behaviours. Because of this, it should only ever be used as a last resort.
What should I do instead to minimise corruption?
If you find yourself in a situation where the system is frozen/stuck or is unable to boot normally (commonly seen with autoload savestates with Drastic), then please try either the safe shutdown or safe restart combos first:
Safe Shutdown: L2+R2+SELECT
Safe Restart: L2+R2+START
These shortcuts can be found on the main page at muos.dev and it is highly recommended you check there for a full list of other handy hotkeys!
That still didn’t work…
If you’ve tried both shortcuts independently, held them for a reasonable amount of time (5~10 seconds) and there is still no response from your device, then unfortunately it may be time for the last resort - the reset button.
At this point, it is likely that the damage has already been done and the reset button is the only thing that may allow your device to boot.
Following use of the reset button, be cautious when using the device, and if you notice any weird behaviour (boot errors, not saving games) then it is preferable to reflash the SD card after backing up your content, saves, bios files, artwork.