RPi CM4 with Zymkey 4i - no boot

Hi guys!
I got the trouble with my CM4 module, witch stands on Waveshare NANO-C shield and wired with Zymkey 4i module.
It worked before I did rpiboot recovery.
Now it has not video signal on HDMI, no boot, except the message from the UART port:

Failed to validate bootconf.txt
FATAL error-code 24

This is the brand new device, without useful info on it, and I have 2 flashdisks with keys.
It can boot only from eMMC memory.

How can I bring CM4 back to the life?

@cobalt2435 - Sounds like your bootloader/EEPROM code isn’t correct after your rpiboot recovery. You will need to get your Waveshare board and CM4 booting again following Waveshare’s instructions before adding the Zymkey. Once you have your CM4 running, if you need help with the Zymkey, post back here.

Hi Bob!
I was on RPi forum few days, and no decision.
Here is an idea that the problem linked with secure boot and Zymkey module.
My Zymkey was without a battery and always blinked blue, also USB flashdrive has a key. As I read, the indication shows unconfigured device.
But is it possible the Zymkey module locked the boot?

@cobalt2435 - The Zymkey does not do any locking of the boot. Any references to Zymbit Supervised Boot are only applicable to our SCM product. What the Zymkey can do is lock your encrypted root partition.

Is your setup working without a Zymkey? What exactly is the USB flashdrive key used for?

Ok, thank you. Perhaps it is really problem with boot, and if you say that Zymkey doesn’t edit the boot, so problem with another side.
On RPi forum they said “It is not possible to disable secure-boot once enabled or use a different code signing key.” So it is problem with original pem key for boot.img

That is true of PI’s secure boot. Once you set the OTP bits, you cannot go back. That would not involve the Zymkey.

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