beaglebone boot from eMMC

[Guy Yur]

Hi,

On Wed, Mar 18, 2015 at 9:23 AM, Hellmuth Michaelis
<hm at hellmuth-michaelis.de> wrote:
>
> Its really weird. I fetched the Angstroem flasher to put back an original image onto the eMMC and that worked. I dumped the MBR for Linux and the MBR which was generated by the install script and they are both pretty OK and legal. I reordered files on the MSDOS partition. I played with different „BIOS“ geometries (because Linux and FreeBSD have a rather different sight on this) to produce the partitions.
>
> Nothing helps - it does not boot FreeBSD from the eMMC MSDOS Partition. The only thing which made a difference was, when i used the Linux-generated MSDOS partition, removed the files in it and populated it with the FreeBSD-generated MLO and things - then it booted from it. I failed completely to add an UFS partition after the Linux-generated MSDOS partition, tried gpart, fdisk, bsdlabel. The UFS mmcsd1s2a can be generated, populated, fsck’d, tested, checked - after the next powercycle it simply disappeared.
>
> It seems to me that there is a bit more magic involved than only generate the partitions. In the Linux script to generate the image onto the eMMC, they check for:
>
> HEADER=$(hexdump -e '8/1 "%c"' /sys/bus/i2c/devices/0-0050/eeprom -s 5 -n 3)
>
> and possibly write to an eeprom - has someone an idea why this is needed ?
>
> Hellmuth
>
>

Is your msdosfs slice on the eMMC aligned to 1 MB?

I had the same "CCC" problem when I aligned the partition
and used newfs_msdos.
Removing the sector count adjustment calculation in newfs_msdos
as was done in NetBSD worked for me.

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=183234


Regards,
Guy