The following steps were done on a Macbook Air running Catalina OS. It should work the same on newer versions as well. 

Before starting the following steps, unmount the SD card in Disk Utility. Insert the card into your computer, select the drive on the left and press Unmount. 

The icon name should change to "Mount" if it unmounted successfully. 

1. Open Terminal. From the keyboard, press Command+Space Bar then start typing "terminal" to search. Once you see Terminal highlighted, press enter to open a terminal window.

2. Type diskutil list    then press enter

  • Below is what our computer displays. Yours will differ

chriss-air-144:~ chris$ diskutil list

/dev/disk0 (internal, physical):

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:      GUID_partition_scheme                        *121.3 GB   disk0

   1:                        EFI EFI                     209.7 MB   disk0s1

   2:                 Apple_APFS Container disk1         121.1 GB   disk0s2

/dev/disk1 (synthesized):

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:      APFS Container Scheme -                      +121.1 GB   disk1

                                 Physical Store disk0s2

   1:                APFS Volume Macintosh HD - Data     84.2 GB    disk1s1

   2:                APFS Volume Preboot                 81.0 MB    disk1s2

   3:                APFS Volume Recovery                528.9 MB   disk1s3

   4:                APFS Volume VM                      3.2 GB     disk1s4

   5:                APFS Volume Macintosh HD            11.3 GB    disk1s5

/dev/disk3 (external, physical):

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:                                                   *15.9 GB    disk3

3. Locate your SD Card. In this case it is disk3

4. Type sudo newfs_msdos -F 32 -c 8 -v TM3D /dev/disk3    then press enter

  • TM3D names the card to "TM3D" and disk3 should be replaced with your SD Card identifier

chriss-air-144:~ chris$ sudo newfs_msdos -F 32 -c 8 -v TM3D /dev/disk3

5. Enter your computer password    then press enter



newfs_msdos: warning: /dev/disk3 is not a character device

512 bytes per physical sector

/dev/disk3: 31055600 sectors in 3881950 FAT32 clusters (4096 bytes/cluster)

bps=512 spc=8 res=32 nft=2 mid=0xf0 spt=32 hds=255 hid=0 drv=0x00 bsec=31116288 bspf=30328 rdcl=2 infs=1 bkbs=6

chriss-air-144:~ chris$ 

You are now ready to use the card to run GCODES, flash firmware or update screen files on your 3D Printer. 

  • If using to run prints, slice and save .GCODE files directly to the root menu of the card 
  • If flashing firmware, copy the firmware (.bin) file onto the card and follow recommended process*
  • If updating screen files, copy the appropriate files to the card and follow recommended process*

*Depending on machine, the process may differ. This guide is for formatting the SD card ONLY.