Don't attempt to update the firmware if you can't be without the printer for at least a few days in case something goes wrong.
If the printer doesn't show the firmware versions at boot time, doesn't respond to any on-board controls, display shows both temperature at 0° and/or won't connect via USB, please make sure you have formatted the included microSD card as FAT32 with 512 Bytes Cluster/Allocation unit size.
If that doesn't work try other microSD cards up to 32GB (yes some 32GB cards will work and some claim to use 64GB cards. The printer can read both FAT(16) and FAT32. Also exFAT has worked for some people.
The printer can be picky about which cards it will read and update from. If you have multiple microSD cards try them all.
I and others have had good luck with this Kingston 2 GB microSD Flash Memory Card SDC/2GBSP (Single Pack) from Amazon.
I purchased the card from Amazon seller “i77e”. It should not matter which seller to purchase from but I wanted to share in case it does.
If you are having trouble after you think you have tried everything, you can contact me in one of the following online community groups or private message through any of the social platforms listed below.
MP Select Mini Owners Facebook Group - Name: Matthew Upp
MPSelectMiniOwners subreddit - User: tiny_tim_
Monoprice MP Select Mini Google+ Community - Name: Matthew Upp
UPDATING THE FIRMWARE IS NOT SUPPORTED BY MONOPRICE
Monoprice may tell you that you have voided your warranty if you attempt to or successfully update the firmware.
PROCEED AT YOUR OWN RISK
Do not update the firmware before completing a few prints.
Updating the firmware before using the printer introduces another variable to the troubleshooting session you may have to go through.
If the ridiculous amount of warnings didn't scare you away please proceed to the downloads and instructions below.
I might as well throw this in also… “Don't say I didn't warn you.”
Link to V1 firmware - Look within the folders “Firmware - V1 ONLY” → “Individual” → “Motion - V1 ONLY” → Choose version 26 or higher.
v50 - Motion Controller firmware for MPSM Pro/V3
I prefer v50 because the bed leveling probe points are further from the center of the bed. v51 for some reason probes 4 points in a small square near the center of the build plate. v51 is not available for download.
If after the update any of the axes move the opposite direction when homing or moving, you may need to invert the stepper motor direction. Depending on your printer you may have to invert only X, only Y, or possibly X and Y. I have not had to invert the Z-Axis or the extruder/feeder mechanism motor but pay attention to all after you have updated the firmware.
Example: “M562 X”
M562 X ;Inverts X-Axis motor direction M500 ;Saves changes to EEPROM Reboot printer to complete the process (turn off, then on)
After updating the Motion Controller firmware you may need to change the steps per mm.
YouTube link: https://youtu.be/zAj9wqvPNfA - Updating motion controller firmware - The method shown in the video is a different method of the update process.