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Compute Module 3 - eMMC boot from USB

Posted: Tue Jan 15, 2019 8:31 pm
by darko_sudarov
Hi all, I have RevPi Core3 (Compute Module 3). It has 4Gb eMMC. Since it is to little for developing apps I would like to boot from USB drive with raspbian stretch image. I edited /boot/config.txt adding
program_usb_boot_mode=1
when I call
vcgencmd otp_dump | grep 17:
I receive
17:3020000a
So I think this part is ok.

Is there a way to edit boot sequence or disable eMMC since I can't remove it?
Can I replace 4Gb eMMC with 16Gb eMMC?

Re: Compute Module 3 - eMMC boot from USB

Posted: Wed Jan 16, 2019 4:17 am
by fruitoftheloom
darko_sudarov wrote:
Tue Jan 15, 2019 8:31 pm
Hi all, I have RevPi Core3 (Compute Module 3). It has 4Gb eMMC. Since it is to little for developing apps I would like to boot from USB drive with raspbian stretch image. I edited /boot/config.txt adding
program_usb_boot_mode=1
when I call
vcgencmd otp_dump | grep 17:
I receive
17:3020000a
So I think this part is ok.

Is there a way to edit boot sequence or disable eMMC since I can't remove it?
Can I replace 4Gb eMMC with 16Gb eMMC?

https://www.nec-display-solutions.com/p ... ODEL.xhtml

Re: Compute Module 3 - eMMC boot from USB

Posted: Thu Jan 17, 2019 9:33 pm
by thagrol
Replace the CM3 module with a CM3L then boot from USB? That's assuming opening the case won't void any warranty.

Erase the eMMC and boot from USB? I don't know if that's possible and don't have access to a CM3 to try.

Use the same trick used to USB or network boot early model Pi: a single FAT32 partiton containing the latest bootcode.bin on the eMMC.

Re: Compute Module 3 - eMMC boot from USB

Posted: Fri Jan 18, 2019 5:49 am
by W. H. Heydt
thagrol wrote:
Thu Jan 17, 2019 9:33 pm
Replace the CM3 module with a CM3L then boot from USB? That's assuming opening the case won't void any warranty.
Yes, that can be done. I have a CM3L that boots from an SSD by mounting both to an early model WD SATA Adapter.

There is no "case" to open. The CM series boards are just that...boards.
Erase the eMMC and boot from USB? I don't know if that's possible and don't have access to a CM3 to try.
Just make the eMMC non-bootable. Delete a critical file, or just wipe it clean. Simpler to replace it with a CM3L.
Use the same trick used to USB or network boot early model Pi: a single FAT32 partiton containing the latest bootcode.bin on the eMMC.
I did something like that with a CM1, prior to the release of the CM3L. I had the whole /boot partition in eMMC with the the root partition on an SSD.

Re: Compute Module 3 - eMMC boot from USB

Posted: Fri Jan 18, 2019 1:21 pm
by thagrol
W. H. Heydt wrote:
Fri Jan 18, 2019 5:49 am
thagrol wrote:
Thu Jan 17, 2019 9:33 pm
Replace the CM3 module with a CM3L then boot from USB? That's assuming opening the case won't void any warranty.
Yes, that can be done. I have a CM3L that boots from an SSD by mounting both to an early model WD SATA Adapter.

There is no "case" to open. The CM series boards are just that...boards.
For a bare CM, sure. But the RevPi Core3 referenced by the OP appears to be a case and carrier board for the CM3. Hence my comment about opening it.