On Wed, Oct 26, 2016 at 2:57 PM, Jason Kridner <[email protected]> wrote:
> > > On Tue, Oct 25, 2016 at 1:09 PM Robert Nelson <[email protected]> > wrote: > >> On Tue, Oct 25, 2016 at 3:04 PM, Paul Plankton <[email protected]> >> wrote: >> > That's cool! I use an own, customised MLO file - is there a way to put >> it >> > into MBR too? It has a size of about 40 kBytes, so more than the 512 >> bytes >> > of the MBR... >> >> sudo dd if=./MLO of=/dev/mmcblk0 count=1 seek=1 bs=128k >> sudo dd if=./u-boot.img of=/dev/mmcblk0 count=2 seek=1 bs=384k >> > > To clarify, the 512 bytes is just for the first sector of the MBR that has > the partition table in it. We actually skip by that to an offset of 128k. > Based on Robert's instructions, 256 *k*bytes (384-128) is reserved for > the MLO. Of course, MLO needs to fit in the internal RAM of the processor > since this is the first place the DDR is configured, so your MLO would > never get to be that large. > > This version allocates 768 kbytes (2 x 384) for u-boot.img. For some > reason, I thought this might have needed to be increased at some point. > > Someone will let me know if I'm wrong about any of the above. :-) > > >> >> I have not looked at Robert's build instructions lately, and of course there is no way I could know what goes on at beagleboard.org / circuitco. But in the past the instructions guided us to make a 1M hole at the start of the disk( MBR ). Then dd copies the bootloaders to their appropriate places. So what I always did was extract the whole MBR with dd . .. dd if=/dev/mmcblk0 of=/path/to/mbr.img count=1 bs=1M After that when I needed to make a new sdcard, or whatever, I'd extract the bootloaders using a bs=512k. However it did work a few times, but failed at least once if I remember right. As I was pulling the first 512k out of the img file which was probably just the partition table. As at the time I did not understand the dd seek parameter at all. I still find it confusing, but now instead of trying to wrangle the bootloaders out of the image file, I just "blast" the whole 1M MBR when and where I need it. After that I think Robert was trying to create a 4M hole for the MBR, but that introduced some sort of bug. Wonder if that's been fixed yet ? -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORrtCUSfmkELCx5_qksk3xv8rqfJ0j8LXAbiFS4GZrWZpA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
