I observed that the SD card was properly inserted, but during my testing i found that, if the SD card’s writing speed is slow or it malfunctions while the flight controller is running, this error appears (AP logger followed by watchdog reset). Currently, there is no safety mechanism in place to stop logging (to stop watchdog reset mid air) when the SD card malfunctions during running the flight controller.
What did you tested? Removing and re inserting the SD card while the FC is running?
[quote=“aero11223344, post:19, topic:138782”]
However, when LOG_BACKEND_TYPE was set to zero
[/quote]LOG_BACKEND_TYPE = 0 means no backend at all, so no logging.
Are you able to reproduce the failure also with SD card always attached and eneabled by correct settings with heavyly shaking your FC / drone.
This was a pretty confusing topic from the start, but you may have exposed a bug in our handling of logging failures. Recommend you create a new GitHub issue describing the problem you encountered. Please include a short .bin log or parameter file in your report. If any tested SD card contains a crash dump file, include that as well.
Thank you for your guidance! 
I have created a GitHub issue describing the problem in detail:
Watchdog Reset Caused by Slow SD Card or Removal (Possibly Intermittent Connection) During Flight #31108
I don’t have a Pixhawk4 here to attempt replication.
I can’t replicate on a Pixhhawk6X here.
@aero11223344 can you confirm this happens on a bare board and with stock firmware, please?
@amilcarlucas were you ejecting/inserting the SD card while armed when trying to replicate the issue?
Pixhawk4 CPU overload - #15 by aero11223344 Yes, I can confirm that this issue occurs on a Pixhawk 4 with stock ArduPilot firmware. I tested with multiple firmware versions (v4.0.5, v4.4.4, v4.5.5, and v4.6.2), and in all cases, the problem could be replicated. Removing or ejecting the SD card triggers the same behavior, so it is not limited to a specific version.
Yes, the issue was replicated by ejecting and removing the SD card while the vehicle was armed. That action reliably reproduced the watchdog reset.
No, i did not eject the sdcard while armed.