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How to diagnose failure to boot from USB?

I have written a Pi image to a little (spinning) USB drive I have and have connected it to my Pi 4. It's the same image as I recently installed on a new SD card.

I have gone through the various update checks for the eeprom and related things (I think, I've followed a couple of web sites descriptions).

I have changed the BOOT_ORDER entry in the eeprom using rpi-eeprom-config to 0x41 which should try USB first and then the SD card.

... and it doesn't boot from USB, it thinks for a fairly long time and then boots from the SD card (fortunately since the Pi is rather inacessible out in the garage).

If I manually mount the USB drive it appears to have the correct partitions and types with all the usual files etc.

The system does have two USB drives, is there any logic to which it will try to boot from? (The drive with the boot image is /dev/sda so is the 'first' USB drive)

Any ideas gratefully received.

Reply to
Chris Green
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I don't boot from the USB drive, so I have no idea what the eeprom loader does. In my setup I boot from the SD card - i.e. the /boot VFAT partition with the kernel etc on.

The cmdline.txt file in the boot partition specifies to the kernel where the root partition is - you need to change that. you need to know the uuid of the root partition then change the "root=...." parameter to be

root=UUID=magic_uuid_number

The kenrel will then know where to look for the root filesystem.

Reply to
Jim Jackson

When I tried this (admittedly on a Pi3) with 2 USB drives (one SSD and one HDD) I got the same sort of problem. In the end I gave up and now boot from a (small) SD card (FAT boot partition) having changed the cmdline.txt file to point to the UUID of the USB SSD I use as root device.

Reply to
Chris Elvidge

You might try the "bootcode.bin-only" boot mode:

formatting link
It worked for me in one case and failed in another, so your odds of success are likely to be about 50:50 8-)

As a sanity check, you might try putting the microSD card in a USB adapter and seeing if that will boot; if it does, most likely there's a problem with how long the disk takes to wake up. If it doesn't, maybe check the OTP bit for USB boot.

I've been having trouble along the same lines (getting a Pi3 to boot from a hard drive) for some time now with FreeBSD, so if you find something interesting please post!

bob prohaska

Reply to
bob prohaska

Hello Chris!

Monday December 13 2021 21:22, you wrote to All:

On a 3B+ I have a HDD in a 825? casing along with the daughter board. I followed the instructions to install the O/S via a SD card (I think) using specific software then REMOVED the SD card and rebooted.

Since then no problems.

I do not use two USB drives so suggest you try one at a time without the SD card present.

The software build the image onto a HDD and partitions it but you do not seem to having any control of the partitions, sizing etc - it just does it.

Vince

Vincent

Reply to
Vincent Coen

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