Just bought myself a pixhawk 4 board, and after playing around with it a bit it seemed that it is bricked.
Unfortunately I tryied several thing so I cannot exactly tell you what bricked it.
Symptoms after boot:
1- on FMU leds:
ACT led off
B/E led off (sometimes a pale amber, but almost never the case)
PWR led blinking green fast for 4 seconds
2-on I/O leds
ACT blinking blue at 1Hz
B/E steady orange
PWR steady green
3-debug ports
FMU debug port
on the FMU debug port (on the right side of the board) I am connecting with a FTDI, setting the baud rate to 57600 and I don’t get any traces currently, but I used to get that:
IO debug port
with a FTDI, settting the baud rate to 115200 I get the following trace when I power the board on to the USB:
PX4IO: starting MEM: free 1656, largest 1656
4- Connection to qground or APM planner
No connection, I used to have some in the past, but with an upgrade aborted.
5- What I tryied
What I tried so far, is to format the SD card, change the power supply, connect to the ground stations but nothing changes.
As I don’t have any connection I cannot connect with nsh,
If you’re using MissionPlanner, you are probably using ArduPilot and not PX4, so they can probably help you better in the ArduPilot forums.
The first thing I would try is to update the firmware. If the update does not work, then you should add as much information about why the update does not work or what goes wrong. That might give more insights in what is going on.
I think you should re-read my comment, because you are out of scope here: “Connection to qground or APM planner”
1-I m not using ardupilot, I talked about the trying to connect with qgroundcontrol or APM planner
2-“The first thing I would try is to update the firmware”
Again, apparently you didn’t read because I said that I don’t have any connection to any ground station (as well as no ttyUSB popping up in /dev/tty). The only traces that I can get are written above, connecting to the UART of both IO debug port and FMU debug port
Well, I’m not seeing ttyACM0, and in dmesg I see this:
[117972.249608] usb 1-4: new low-speed USB device number 31 using xhci_hcd
[117972.377702] usb 1-4: device descriptor read/64, error -71
[117972.613637] usb 1-4: device descriptor read/64, error -71
[117972.849740] usb 1-4: new low-speed USB device number 32 using xhci_hcd
[117972.981681] usb 1-4: device descriptor read/64, error -71
[117973.221622] usb 1-4: device descriptor read/64, error -71
[117973.329694] usb usb1-port4: attempt power cycle
[117973.985655] usb 1-4: new low-speed USB device number 33 using xhci_hcd
[117973.986281] usb 1-4: Device not responding to setup address.
[117974.198431] usb 1-4: Device not responding to setup address.
[117974.405590] usb 1-4: device not accepting address 33, error -71
Please note two things;
1- I reflashed all the bootloaders (PX4IO and FMU), and that the led are now same as described above on FMU leds, and steady green and 10hz amber for IO leds
2- I managed to reflash Px4 through qgroundcontrol, so apparently the USB popped up correctly, but it’s not the case anymore
Got a STM debugger, got the PXIO bootloader, compiled the boolader code for fmu v5 and flashed both hex through the IO debug port and fmu debug port.
(https://github.com/PX4/Bootloader)
After that it changed the leds behavior and I was at least able to connect to the board once to reflash Px4 through qgroundcontrol.
when I plug the USB now, it says device not recognized and the traces I wrote on my previous post with dmesg.
For the record, I also connected to the USB port (not the mini USB on the side) to see if something was different, but same behavior
Your original trace indicated you corrupted the application that hardfaulted but had RAM memory. “Memory wiped - dump not saveuphardfault: PANIC!!!”
This could be a bad F7 or a fuse issue.
Use the STLink to do a full chip erase on both FMU and IO. Ensure the fuses are set for dualbank on the F7. Then load the bootloader on both. LEDs should indicate both SoC in bootloader mode. FMU green flutter. IO orange flutter. The unit should then enumerate when connected to USB. If you can that point you should be able to upload maser. “make px4_fmuv5 upload”
I erased both chips, reflashed px4iobl.hex and px4fmuv5_bl.hex.
Then I was able to connect to qgroundcontrol and reflash px4, and I can see that it is popping up on ttyACM0.
Unfortunately I m still unable to connect to qgroundcontrol more than to reflash the board. Any tips?
I tried setting coms ->serial->ttyACM0 but it says “Connect not allowed: Connect not allowed during Firmware Upgrade”
What addresses are you loading the HEX files at? Just asking as the lights seem to indicate both are working. But if the bootloader on the FMU was not loaded correctly it could make the hw look bad.
Let’s get QGC out of the loop for a minute.
Are you able to build and install PX4?
Use the STLink to do a full chip erase on both FMU and IO. Ensure the fuses are set for dualbank on the F7. Then load the bootloader on both. LEDs should indicate both SoC in bootloader mode. FMU green flutter. IO orange flutter. The unit should then enumerate when connected to USB. If you can that point you should be able to upload maser. “make px4_fmu-v5 upload”
This will tell us if the HW is ok.
If the board does not enumerate (check dmesg) The HW is bad. That is: the cable or FMU or HUB or PC. You can then test HUB, PC and cable with another device. If all the HW is good, then the FMU HW is bad.
Coud you help me please.
After an unsuccessful firmware flashing using QGC. Through the IO Debuging port (after usb pluging) I see the following messeges:
Hi David_s5 Dev Team;
Please excuse my intrusion here in this post… I was having several conversations with rrchoe a few weeks ago… suddenly my messages were not accepted when I replied. I have no idea what happened… Was I band or > ?.. To make a long story short, about 2 yrs ago I started building an S500 Quadcopter with Pixhawk 4 (holybro) Flight Controller. I had several problems with QGC. I heard about Mission Planner and decided to try it. I attached the Pixhawk 4 Flight Controller via USB to my Laptop(Windows 10) to do configurations, setup, radio, flight modes, etc. Some how Mission Planner installed Ardupilot/ChibiOS onto my Pixhawk 4 F/C where it use to read “PX 4FMU-v5”… since then It’s like it bricked…? I’ve contacted px4.io, rroche we had discussion about Flashing PX 4FMU-v5 back onto the PX 4…by following directions in the Master Docs… none of that stuff worked, then I was banned or whatever from here…? Could you possibly help me with this issue, if you receive this reply…? Thanks in Advance, James…
I didn’t know that was possible. 
