A beginners adventure into the world of multirotor fpv drone racing and freestyle

Betaflight SD card Blackbox problems ( Fatal error Reboot to retry)

Problem: SD card section in blackbox menu states: Fatal error Reboot to retry


fc: Matek F722-SE
Bf: Betaflight 4.0.4
rx: Frsky R-XSR
tx: Frsky x-lite
vtx: RDQ Mach 1
vrx: FatShark Scout

Solution: Your SD card needs a valid FAT32 partition in order for Betaflight to recognize it and use it for black box.

To see if this is your problem:

  • Betaflight CLI
    • sd_info
  • If the card is detected by Betaflight (shows manufacturer, size, etc) but error message is ‘no FAT MBR partitions‘ – it is because you need a FAT32 partition on your card
  • exFAT and NTFS volumes cannot b read by flight controllers in Betaflight (at this time)


Default Windows behaviour does not allow you to create a FAT32 volume larger than 4 GB. There are two sets of instructions. One is if you have a card 4GB or smaller and can use Windows disk utilities and the other is a small 3rd party tool that can quickly format a much larger FAT32 partition for you.

First make sure there is nothing valuable on the card!

  • Remove SD card from flight controller and mount it to your Windows PC (via USB, or SD slot if you have it)
  • Run -> diskmgr
  • Select your SD card from list of disks in Windows
  • Right click any existing volumes
  • Delete volumes until there are no volumes on the SD card
What your SD card should look like after removing all of the volumes.

If you have a 4GB card or lower:

  • Right click unallocated space
  • Create a ‘New Simple Volume’
  • Use 4096MB as the volume size
Make the volume 4096 MB (4GB in size)
  • Select file system as FAT32 using drop down
  • If FAT32 is not an option, go back and make sure that your volume size is not over 4096 MB!
Format as FAT32

If you have a greater than 4GB card:


  • Put SD card into flight controller
  • Open Betaflight
  • CLI
    • sd_info
  • Filesystem: Ready indicates things are fine or Filesystem: Initialize and returning to Ready after
Card is detected and file system is ready for your black box logs!
  • If Filesystem: Initialize is taking a long time
    • Betaflight CLI – sd_card dma = off
    • Change Blackbox logging rate down to 4 kHz or less
    • These two changes worked for me
What Betaflight should look like when the card is ready.

With all of this, you should be ready to go ! Hopefully larger volumes will be able to be used in the future, but this is quite common with these type of boards – ie a Raspberry pi expects to be booted off of a FAT32 volume.

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