m3adapter has released the latest firmware for M3i Zero 3DS 3.0.0-5. Please take note that the upgrade needs to be done via the firmware USB. 

Note:

• All machines are upgradeable even your machine has already been in firmware 3.0.0-5 or 1.4.3. And no need to find another bootable machine to perform the upgrading process. 
• Risk-free: flash card will not be damaged even the upgrading process is not successfully.
   

1. Unzip the firmware ( F_CORE_v3.0.5 ) and driver ( G6&M3DS-R_M74) downloaded (using Winrar) on your PC
   • Winrar can be downloaded from www.download.com by searching for Winrar at the Search.
   • Unzip the files mentioned under the Software Preparation above, you will have one folder and one file as follows.
     

     F_CORE_v3.0.5	G6&M3DS-R_M74
     F_CORE.DAT	SYSTEM

      

2. Select all the two unzipped files and copy them to the root of microSD / SDHC memory card after you have formatted the micro SD / SDHC card in FAT32.

   
    

3. Insert Micro SD/SDHC card into the M3i
    
    
4. Put the upgrade cable into the M3i. The shinny metal contact of the cable, i.e. the side with the ARROW on it, should face the BACK of the M3i.
   
    
5. Plug the USB port into your PC, or anything that has a port that will give it power
    
6. The M3i should blink for about 15~20 seconds. After it stops blinking, your M3i is flashed.

 Note:

LED blinks – in progress
LED lights off – no power or incomplete
LED lights on – error (no "f_core.dat" or wrong file etc.)

If the LED light turns RED (without flashing), it means the update is unsuccessful. Please repeat the whole process from step 1 after you have checked the Possible Reasons For Upgrade Failure listed belowfollowing:

• Put the upgrade file into sub directory, not the root directory, and the firmware writer can not detect the upgrade file. 
• USB port can not provide a stable power, please change a stable USB port.
• There are too many disk defragments in the MicroSD memory card, which needs to be formatted before upgrade. For memory card formatting, please refer to the guide under Format a MicroSD / SDHC card above.

Please refer here for the step-by-step setup guide for M3i Zero 3DS