Raspberry pi4 Ubuntu not booting


Today I was working on my 3 raspberries when I had to reboot one of them. After rebooting, my boot was stucked with the message below after the bootloader:

spi-bcm3825 fe204000.spi: could not get clk: -517
_ (blinking)

After restarting all my rpi4, I noticed that they were all blocked with the same behavior :face_with_symbols_over_mouth:

My problem seems similar to this thread:

I would like to overcome this without reflashing the SD card but more important: understand why it happened?

I checked my power supply to see if it the voltage and the quality is ok and unfortunately I discovered that power was reaching peaks at 5,30v which is above 5,25v (Overvoltage). See the topic below:

I then used a lab power supply calibrated to 5v to be sure signal is fine and started the rpi4. Problem is still there.

I did long configuration work on these platform and would like to get the system back up and running without re-flashing the SD card. Would it be possible?
What could have gone wrong here since I did not worked on the two other tablets?

I also tried to use the keyboard to interrupt the auto boot but seems that no key is detected at that moment of boot…

I would really appreciate any help, thank you in advance :weary:

O.S: Ubuntu x64 20.04 LTS
Board: Raspberry pi 4 b
ZYMKEY4 without battery in developer mode.

Hello Gilles,

It looks like when I reproduced this, it continued on after 10 seconds or so and booted. Can you wait for 30 seconds or so and see if you boot or get any additional output? I’m curious about the message right after that one if you see anything.


Hello Bob,

Thank you for your message.

Can you wait for 30 seconds or so and see if you boot or get any additional output?

→ Left it on for at least one hour: Nothing happens, it hangs, no keyboard input press is possible, CTRL+ALT+DEL does not reboot.

My fourth zymkey got also locked with same behavior… I definitely did something wrong :frowning:
I attach a picture of the boot message at the beginning:

Could you please answer my questions from my first post? :laughing:
I have other many other questions, like:

  • what are the conditions for the zymkey to destroy the master key in developer mode?
  • is the battery cell mandatory for the zymkey to work in developer mode?
  • can we swap SD card without master key to be destroyed?

Thank you so much!


I’m going to follow up with you directly via email for now rather than here in the community since I cannot currently reproduce this issue and we may go back and forth a few times.

I’ll try my best to address any questions from both posts. I will edit these later to be more helpful once we figure out what happened. Answers for now:

  • This does not seem to have anything to do with power. Your power source seems fine. It seems to be related to an upgrade of your kernel/initrd. I currently cannot reproduce and do not understand why it happened.

  • Encrypting your root partition is obviously to prevent someone in the field from accessing your intellectual property. Good practice would be for you to have access to your code/image locally so that you can reproduce another SD card should it be needed.

  • The only way to destroy the keys on a Zymkey is via our API by enabling that mode for a perimeter detect event. That said, there is no way to access the key to unlock your root file system once you have encrypted even in development mode without that specific Zymkey, SD card, PI combination.

  • The battery is only necessary to maintain the RTC and if you have setup perimeter detect to take action - notify or destroy keys.

  • In developer mode, you can “start over” at any time. The Zymkey does not destroy any keys unless you enable that mode via the API for perimeter detect events and put into Production Mode by clipping the tab. You can put in a new SD card and re-use the Zymkey and PI.

I’ll update this post once we determine what changed during the upgrade of ubuntu for others in the Community.