PI4 Model B doesn't boot

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timyaukey
 
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Joined: Fri Jul 16, 2021 4:25 pm

PI4 Model B doesn't boot

Post by timyaukey »

I recently purchased a pair of Raspberry PI 4 Model B, each with 4GB of memory. One works fine, and the other one does not. The problem child turns on the red LED when I plug in power, and flashes the green LED once, and then nothing more happens. I've swapped cables, power supply and MicroSD card with my functioning PI of the same model, and everything except the PI itself works fine. Including the memory card. The problem is not completely reproducible - once or twice I've powered it on and gotten console messages I don't normally see. Once it said something about resizing the boot partition, and another time it gave another message (I don't remember what) and never finished booting. Once it actually booted to the "new user" login prompt, but I was never able to reproduce this.

I've tried using the memory card from the correctly functioning PI in the problem PI, and it gives the same LED pattern of red on and single green flash. Is the green LED an activity indicator for accessing the MicroSD card? If so then that suggests it is trying to boot from the card and fails to read from it. Since the same MicroSD card boots fine in the other PI the conclusion is there is a problem in that area of the PI and not the card itself.

Is there any further diagnostic work to be done, or can I just ship it back for a replacement?

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mikeysklar
 
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Joined: Mon Aug 01, 2016 8:10 pm

Re: PI4 Model B doesn't boot

Post by mikeysklar »

Good job troubleshooting this so far.

Just curious. Are you are you running the current Pi OS on the SD card that is being swapped between the good Pi and the unstable / non-functioning Pi?

It sounds like the new Pi4 has a EEPROM that is getting stuck. You can take a look here for a suggested way to boot a replacement EEPROM and if it gets overhwelming we can do a return with you.

Code: Select all

Model 4 (B) green LED blinks regular when the PI doesn't detect the SD-card, and irregular when it boots, if the LED stays inactive (with power on) perhaps you need to repair the BOOT EEPROM code (note ONLY the RPI4 has a boot EEPROM, so don try to update the EEPROM on any other model than the RPI4).
The recommended method to recovery the BOOT EEPROM to the factory default settings is to use the Raspberry Pi Imager.
https://www.raspberrypi.org/downloads/

Select Choose OS -> Misc utility images -> Pi4 EEPROM boot recovery

See the BOOT EEPROM documentation for the manual method.
https://www.raspberrypi.org/documentati ... teeprom.md

With no SD card inserted, note how the ACT LED behaves (hint, it won't blink!, except with a PI4B). Now insert a programmed card and power up, and that behavior should change. If it does not, this indicates that Pi cannot see the necessary files on the SD card. 
For a demonstration, watch this video of a model B: the ACT LED is the one on the left-hand side. Note that on the model 2 the ACT LED will start ON on power up, instead as off like the model 1. 
https://www.raspberrypi.org/forums/view ... 28&t=58151

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timyaukey
 
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Joined: Fri Jul 16, 2021 4:25 pm

Re: PI4 Model B doesn't boot

Post by timyaukey »

I tried to reprogram the EEPROM, but no joy. I use the Raspberry Pi Imager software to prepare two different MicroSD cards according the documentation you referenced, and both yield the same result: The HDMI connected monitor shows all red, and the green LED blinks 3 long followed by 2 short. According to the docs, this blink pattern on a Pi4 means the EEPROM is write-protected. Further pursuing this condition I found documentation suggesting I add a config.txt with the line "eeprom_write_protect=0" but it makes no difference.

Any more ideas?

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timyaukey
 
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Joined: Fri Jul 16, 2021 4:25 pm

Re: PI4 Model B doesn't boot

Post by timyaukey »

And in response to your other question, I'm using a copy of Raspberry Pi Imager I downloaded a few days ago to generate the "standard" Raspberry Pi OS with a graphical UI.

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mikeysklar
 
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Re: PI4 Model B doesn't boot

Post by mikeysklar »

Thanks for trying the EEPROM with the Pi OS imager utility. I appreciate how you already tested against the other Pi4 and this one has been persistantly an issue.

We can do a replacement if you puchased the Pi from us in the last month. Go ahead and send an e-mail to [email protected] with your order# and a link to this forum thread requesting a replacement.

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