Wednesday, 26 June 2013

Brick + Recovery + TFTP

Managed to brick my BBB within two days of receiving it.
Fix up the eMMC using

The trickiest part was that I didn't realize that the script was working in the background and I just had to wait. I thought I'd see messages pop up on the serial console but nothing came up. And wasted a day thinking why isnt it working. vvu on #beagle-gsoc told me to simply wait. Lol.

A simple ps -a cleared the matter :) 

I wanted to set up uboot so that my uImage boots via tftp.

Lots of guides here and there. and

A bit scattered though. And 3.8 kernel changes quite a few things. is a comprehensive overview of changes.

Anyways. My uEnv if anyone interested.

optargs=quiet drm.debug=7

#run tftpboot 0x80200000 uImage
#uenvcmd=run loaduimage run loadfdt run mmcargs bootz 0x802800000 - 0x80F80000

bootargs=console=ttyO0,115200n8 root=/dev/mmcblk0p2 ro rootfstype=ext4 rootwait

uenvcmd=echo "Booting from Network";tftpboot 0x80200000 uImage; tftpboot 0x815f0000 dtb; bootm 0x80200000 - 0x815f0000

One thing to note that someone helped me out in IRC.
3.8 is a DT based kernel. So its not just the uImage file to load.

If you are loading just a uImage file. Then you have to load the uImage-dtb file which can be compiled. Which is basically the DT appended to the kernel.

Otherwise you can load two files. uImage + DT. The DT file is the device tree that replaced the old board file system. It took a while to digest things. Links to a presentation by Koen on it as well.


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