开云体育

Just for the sake of argument, let's say I do something stupid and my zbitx will no longer boot. But I have done a SD card copy to an external usb with new UUID.

How do I boot from the USB so that I can copy the system back to the internal SD card thereby restoring my zbitx and making it bootable again?

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Leo, AI5II

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If you want a quick answer, copy the uSD card from the working system (you can do it with an SD card reader) and then swap the two cards.

Due to the small size, booting from an external USB increases the portability. As far as I know, this was also the goal of zbitx, to be small and portable.

By the way, if you want to experiment with this external USB boot, you can read the solution on the JJ wiki how it was implemented at sbitx.

The microUSB is probably usb 2, so I think you can't achieve a speed increase with this.

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Gyula HA3HZ

I follow what you are saying.? However the sdcard in the zbitx is? internal. I was hoping that a sdcard in a card reader in the USB port can be booted instead of booting from the internal card.

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Leo, AI5II

With sbitx, it is worth booting from an external USB 3 because there is a speed difference.

Here, the RPi4 also boots from the uSD card on the pcb, while the uSD has a speed of 30 MB/s, while the external USB 3 speed (depending on the quality of the stick) reaches a 10x increase.

I recommend replacing the internal uSD card because I think there is not that much gain with the external USB.

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Gyula HA3HZ

I'm looking at? it from a backup restore perspective.

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Leo, AI5Ii

I finally managed to boot from an external USB on my zbitx.

I had to modify /boot/cmdline.txt? on the internal sdcard to point rootfs to the external device UUID.

Of course if I remove the external device the zbitx doesn't boot because it is waiting for the root file system which is not there .

Not sure how the zbitx boot process works but it appears that the internal sdcard is needed to actually boot from the external sdcard. Not sure why that is?

Once the zbitx is up and running on the external device I am able to unmount the internal sdcard and everything runs ok.

/dev/sda1 is mounted as /boot and

/dev/sda2 is mounted as /rootfs

It looks like what is needed is a? check to see if the internal card is present and the external card is not then boot from the internal card and its file systems otherwise boot from the external sdcard?

Ideas?

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Leo, AI5II

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Generally speaking, you can enable usb booting with no sd card on a Raspberry Pi Zero 2.

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https://forums.raspberrypi.com/viewtopic.php?t=322604