uboot won't boot until running 'mmc part 0'

[Paul Larson]

U-Boot 2011.03 (Apr 20 2011 - 07:37:43)
Using the test automation we have, I have a pandaboard attached to my laptop trying to deploy a new image, and using commands sent to uboot over the serial console to get it booted:
U-Boot 2011.03 (Apr 20 2011 - 07:37:43)

CPU : OMAP4430
Board: OMAP4 Panda
I2C: ready
DRAM: 1 GiB
MMC: OMAP SD/MMC: 0
Using default environment

In: serial
Out: serial
Err: serial
Hit any key to stop autoboot: 0
Panda # mmc init
Panda # setenv bootcmd 'fatload mmc 0:5 0x80200000 uImage; fatload mmc 0:5 0x81600000 uInitrd; bootm 0x80200000 0x81600000'
Panda # setenv bootargs ' console=tty0 console=ttyO2,115200n8 root=LABEL=testrootfs rootwait ro earlyprintk fixrtc nocompcache vram=32M omapfb.vram=0:8M mem=463M ip=none'
Panda # boot
MMC: block number 0x1 exceeds max(0x0)
** Can't read from device 0 **

** Unable to use mmc 0:5 for fatload **
MMC: block number 0x1 exceeds max(0x0)
** Can't read from device 0 **

** Unable to use mmc 0:5 for fatload **
Wrong Image Format for bootm command
ERROR: can't get kernel image!
Panda #
Panda # mmc rescan
Panda # boot
MMC: block number 0x1 exceeds max(0x0)
** Can't read from device 0 **

** Unable to use mmc 0:5 for fatload **
MMC: block number 0x1 exceeds max(0x0)
** Can't read from device 0 **

** Unable to use mmc 0:5 for fatload **
Wrong Image Format for bootm command
ERROR: can't get kernel image!
Panda # mmc part 0

Partition Map for MMC device 0 -- Partition Type: DOS

Partition Start Sector Num Sectors Type
    1 63 106432 c
    2 106496 2887680 83
    3 2994176 4960256 5 Extd
    5 2996224 143360 b
    6 3141632 4120576 83
    7 7264256 690176 b
Panda # boot

As you can see, mmc rescan doesn't have any effect, but as soon as I run 'mmc part 0' I can magically boot. This didn't happen in the maverick version of uboot (which I have actually running on the master image in the lab)

[John Rigby (jcrigby)]

I believe the rational is that you really do need to pick a partition before reading. If booting needs a certain partition then the boot script needs the mmc part command in it.