Pixhawk 2.4.8 hangs with solid yellow I/O Bootloader Mode LED

Have seen similar issues discussed but not this exactly. About 5-10 minutes after power up the “I/O Bootloader Mode” LED comes on solid yellow and pixhawk is no longer responsive to RC transmitter or Mission Planner. Requires a power cycle to become responsive again. The LED/hang behavior seems independent of how much interaction has occurred via RC or MP, or whether they are even connected.

I am running Ardupilot Rover Beta 3.5.0 rc1 (on ChibiOS) with a boat frame (which is needed for its multiple relay support). It would be helpful to know what exactly this LED indicates - e.g. failure of the bootloader ? …bootloader trying to reload firmware ? Should I be trying to re-install the bootloader ? Bug in ChibiOS or beta rover ? pixhawk h/w failure ?

All pointers welcome.


Just for the record, this turned out to be a pixhawk hardware failure/defect. I/O Bootloader Mode LED would come on a few minutes after power up (as if its rebooting - which maybe it was) but remained unresponsive till power cycled. Chinese vendor of inexpensive pixhawk (hobbypower on Amazon) replaced unit at no cost - nice.

Another update: the replacement pixhawk clone fails the same way (i.e. pixhawk hangs with I/O Boot error several minutes after successful boot). Since the hardware kit was advertised as a quad-copter system I flashed and tested with the latest quad-copter firmware (also plane and rover) all with the same result. Another possibly relevant observation is that no boot log file was created in any of those failures. I followed http://ardupilot.org/dev/docs/troubleshooting-pixhawkpx4-boot.html to troubleshoot, and tested with a known good micro SD card from a working pixhawk, so its not the card. Is it possibly a faulty bootloader ? Should I attempt to re-flash the boot-loader ??? …tho don’t see current guidance for this.

@rmackay9 - hate to bother you about this but thought you’d have some insight.

I really don’t know… maybe try with Copter-3.6.7-rc1 although it sounds likely you’ve already tested with latest which has all the same fixes. Maybe connect with Putty (a simpler terminal emulator) to see if any messages are displayed on the COM port at the moment it fails.

It might be good to check with 3.6.6 NuttX as well.

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Same issue here, have you been able to fix the solid yellow led after a couple of minutes? Is there any documentation anyone has found on this? Been flying since 3 months now suddenly this happened, no idea what caused it. Please could someone help!

Beena - The only new info I have is that my two Chinese clone pixhawks labeled 2.4.8 run fine for hours with the previous rover release v3.4.2 but fail within minutes with the solid yellow I/O Bootloader error when flashed with rover v3.5.0. I see you are flying not rovering, but did you recently upgrade your firmware ?

@rmackay9 Randy - I can’t tell if these failures are due to the app upgrade or the OS change. The only way I can see how to run v3.5.0 over NuttX is to flash v3.4.2 (from Mission Planner) which (I think) erases everything and loads NuttX & 3.4.2, and then install 3.5.0 and decline the “install ChibiOS” prompt. When I do that, I still get the failure but not 100% sure NuttX is really loaded. 1) How can I tell? 2) Is there a documented preferred method to flash a new release over the old OS ?


Tom, so we factory reset ours and then loaded the rover, then switched to copter, disabled all pre-flight checks and it worked fine.