On Thu, 13 Feb 2020 10:39:40 -0800 (PST), in
gmane.comp.hardware.beagleboard.user
[email protected] wrote:
>
>
>On Thursday, February 13, 2020 at 12:15:38 PM UTC-6, Hugo van den Brand
>wrote:
>>
>> The distro that is present on the eMMC should not have any impact when you
>> boot a distro from the SD card.
>>
>/*so your saying that regardless of what is on the eMMC if i put in an sd
>chip that has a working version of BBB compatible Linux then it should boot
>right?*/
>
My understanding of the current boot scheme is that...
IF the boot-select is held down when power is applied (not just a
reset!), booting takes place entirely from the SD card -- including loading
u-boot from the SD card.
In MODERN images, if the boot-select is NOT held down, then u-Boot is
loaded from the eMMC -- and modern u-Boot then determines if a bootable OS
exists on the SD card, and transfers control to it (including, I believe,
the uEnv.txt file -- so if the SD card is a flasher image, it automatically
gets flashed)..
One problem: older u-Boot images assumed the kernel would load device
tree overlays; newer u-Boot loads the overlays. As a result, if one boots
from an image using an old u-Boot -- no device tree overlays get loaded,
and the kernel likely fails to function.
Angstrom is down-right ancient -- not even my first BBB had Angstrom on
it. Those older images (including the early Debian versions) made use of a
small FAT partition for booting. Newer Debian images do not use a FAT
partition (they create a virtual read-only FAT /after/ booting for purposes
of the "starting beaglebone" stuff that shows up in Windows).
PLEASE verify you have a 4GB Rev-C board. I don't know if even the IoT
image will fit on a 2GB pre-Rev-C board.
Given the age of the board, you may need to wipe the start of the eMMC
(SSH to the card after booting from eMMC, and using some "dd" command --
search the group for an example) -- wiping out the boot sector and u-Boot,
which should result in the boot sequence reverting to the SD card. Then use
(I recommend the IoT image just to give more free space) and confirm it
boots. If it boots (and you have 4GB eMMC), modify the uEnv.txt to turn the
card into a flasher. With luck it will reflash the eMMC with a working
Debian and update the u-Boot stuff (Caveat: I've never had to go to the
level of wiping the boot sectors -- regular flashing of Debian images has
been sufficient; I did have to use the boot-select to do that with Debian
Wheezy and I think the first Jessie images).
>/*
>i was expecting the same things as these.
>i used the following links:
> http://derekmolloy.ie/write-a-new-image-to-the-beaglebone-black/
> https://youtu.be/_nPj1cCFrRk
> https://youtu.be/oRGrm8RfGCE
>*/
>
"updated 2015" -- that page may be a bit out-of-date. Many sites have
deprecated Win32 Disk Imager -- the preference these days appears to be
Balena Etcher (though W32DI may be of use if trying to create an image file
FROM and SD card; Etcher does not do that direction, but does work directly
from compressed archives).
As mentioned above -- my recommendation would be to download the IoT
image, write it to a 4+ GB card. Presuming you haven't yet wiped the eMMC
boot sectors... Insert the SD card, hold down the boot-select button (S2),
and insert the power adapter. If it boots it should be the IoT image.
Presuming the IoT image booted, navigate to the uEnv.txt file and
uncomment the last line -- this converts the image to a flasher image.
Shutdown the unit, remove power supply. Repeat the above boot sequence (S2,
apply power). With luck you get the 4LED Larson scanner effect and the eMMC
will be flashed with the new image.
Hmmm -- have you verified the SD card slot is functioning? Maybe boot
the eMMC Angstrom image, insert the SD card, and mount the card -- then
explore it to make sure you can read it.
If the SD card slot is okay, but you can't get it to boot the SD card
image (even with S2 held down while applying power), it may be time to try
wiping the eMMC.
--
Dennis L Bieber
--
For more options, visit http://beagleboard.org/discuss
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