Fix no video feed / black screen / no image transmission / no FPV on Ph3 Pro

Thanks again. I wish I had the will to drop it and move on. I suppose the puzzle is a needed life distraction.

The putty log was generated from a disconnect gimbal top board. I will attempt to connect everything and get a new log in hopes to discover more clues.

I also question if my replacement MC is still an issue as the bird is behaving very similar to when to when I first flashed with a bad bin. Or perhaps some other components were affected not related to the MC but are preventing firmware flashing and updating. I keep believing if I can get a SD flash to work, all components will be updated correctly and all will be good. Hard to tell without a log being printed to identify where the problem initiates.
 
I have made some progress, thought I would share
As for the gimbal with no video transmission, I ended up fixing it by removing the cmos module from the camera. I believe resetting this cable did the trick. Years ago I monkied around with this component removing the IR filter from the lens. I remembered at that time I had some transmission issues that were intermittent. Putty log from connecting this camera looks normal - image transmitted.

I also determined my salvage flight controller (MC) was still bad - hence not allowing any updates via the SD. Swapped that out with another one and it all came back to life. Successfully upgraded to 1.11 and then downgrade (version by version) to 1.07. All looks good but I need to downgrade my controller and phone apps. Still working on that.

Having trouble finding the information and firmware files for the RC controller. Also there seems to be different controller hardware 300a, 300b that concerns me as well. Looking for direction to help RC downgrading.

As for my other gimbal/camera that transmits an image but shows a camera error (in the app) and not reading the SD card, I remain stumped. I would like to read and flash the Ambarella (m0100 and M0110) - I believe they control the sd card slot. I'm assuming I need to connect to the U0 pins that are on the other side of the board (opposite side of the pads used to read the Davinci). Plenty of guides showing how to fix/flash the DM365 but no so much the Ambarella. Looking for help and or suggestions to help Ambarella repair. I'm not even sure it is possible. At this point, I'm willing to try anything as it is not much good as is.
This has been a fun learning experience, appreciate the help along the way.
 
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Having trouble finding the information and firmware files for the RC controller. Also there seems to be different controller hardware 300a, 300b that concerns me as well. Looking for direction to help RC downgrading.
The firmware packages from DJI contain firmware for both GL300a and GL300b/c. Specific module file from the package will be selected based on the identification of modules within the RC.
The only concern is to not downgrade below the time when GL300b was released - oldest firmwares only have modules for gl300a.

I would like to read and flash the Ambarella (m0100 and M0110) - I believe they control the sd card slot.
If you have video transmission, then Ambarella booted and its transcoding service is working. If sd-card doesn't work at this point, this is not a software issue. Check your slot for mechanical damage.

DaVinci doesn't get video from the sensor directly, it gets forwarded a downscaled image from Ambarella. In fact, DaVinci doesn't even have the ability to control CMOS Sensor directly.

But if you decide to ignore that:
To reflash Ambarella, you need to use AmbaUSB. Note that almost every action camera on the market from around the Ph3 release date used that Ambarella chip as well. Like Gopro, Sjcam or any other. So you can search for guides of reflashing other cameras with Ambarella A9 chip, and they should apply.
 
If I understand correctly the same firmware bin packages used for the AC work on the RC, correct? Additionally do the same debug file use to downgrade the firmware on the AC work on the RC?

If I want to use 1.07 or 1.06 on the AC, what is the suggested best version for the RC.
 
If I understand correctly the same firmware bin packages used for the AC work on the RC, correct?
I don't think so. The firmwares were bundled together in few early versions, but then DJI started releasing "P3X_FW" and "C1_FW" firmwares separately.
If I want to use 1.07 or 1.06 on the AC, what is the suggested best version for the RC.
Check their publish dates, and select the one closest.
 
Can't figure out how to downgrade a gl300b. I have done the debug process with the bird, now trying the controller. Placed the "C1 xx" file on a usb drive, inserted, turned the controller on - nothing happens. Must be doing something wrong but can figure it out

I tried the special button combinations to put into recovery mode - that did not work either. Help appreciated. thanks.
 
That is a great write up for r the gl300A. Still confused about downgrading method for the gl300b as it was indicated the usb method will not work on that model
 
Can't figure out how to downgrade a gl300b. I have done the debug process with the bird, now trying the controller. Placed the "C1 xx" file on a usb drive, inserted, turned the controller on - nothing happens. Must be doing something wrong but can figure it out

I tried the special button combinations to put into recovery mode - that did not work either. Help appreciated. thanks.
Which firmware version is on the drone and remote at this moment?
 
Currently at 1.7
Recently downgraded to
P3X_FW_V01.07.006.bin

Remote at 1.9.2
Android DJI 2.4.3
 
Last edited:
1.7.6 on the bird and 1.9.2 is a mismatch of firmware versions.
Yes, I understand the mismatch. My intention was to downgrade the gl300b to match the AC. I was under the impression this was possible as I see others have accomplished it.
 
Yes, I understand the mismatch. My intention was to downgrade the gl300b to match the AC. I was under the impression this was possible as I see others have accomplished it.
Yes I understand. The downgrade process for the newer versions is done through the GO app, not the drone firmware versions.
 

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