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.

New stuff on new build

A week and a half ago had a bad day with the chameleon – shredded a balance plug and ripped off an esc signal wire which later led to a blown esc after resoldering it and flying..

Needless to say, I ordered a new set of Spedix escs (was using older Spedix 35A multishot escs given to me by my dad). In the meantime I managed to lift off a signal pad removing the old escs.

So my RIP my first FC – JBardwell F4 v2 AIO.

I ordered a new FC from Rotorgeeks in Toronto – the Matek F722-SE. With our dollar being so weak, it was almost the same cost of replacing my JBv2 for a better board.

Fast forward a week, all of this stuff has arrived, including my FatShark Scouts that I purchased on preorder from from RDQ.

After two days of nervously considering how to rebuild, I spent all night getting my chameleon back together.

I’m not pleased with the lipo wires – I need to either put an xt60 right on the board or use a shorter/longer wire to get it lined up with the battery better. Will need more investigation before I risk unsoldering and making a less than optimal solution a real problem.

All I need now are new motors (low kv or high kv?) and more batteries (4s, 5s or 6s ?) but will have to wait til my August budget.

Stay tuned for some troubleshooting posts setting up all of the new stuff!