[U-Boot] Question: booting Linux from ext4 mmc partition

[nidalpres]

Hi all!

I was following instructions from
http://eewiki.net/display/linuxonarm/iMX233-OLinuXino in order to get
mainline kernel to boot off of my olinuxino micro board.

I have created two partitions on my SD card:
   Device Boot      Start         End      Blocks   Id  System
/dev/sde1            2048       67583       32768   53  OnTrack DM6 Aux3
/dev/sde2           67584     7829503     3880960   83  Linux

and installed everything as per instructions. However on boot this is
what I get on console:
HTLLCLC

U-Boot 2013.10-dirty (Jan 05 2014 - 19:38:28)

CPU:   Freescale i.MX23 rev1.4 at 454 MHz
BOOT:  SSP SD/MMC #0
DRAM:  64 MiB
MMC:   MXS MMC: 0
*** Warning - bad CRC, using default environment

In:    serial
Out:   serial
Err:   serial
Net:   Net Initialization Skipped
No ethernet found.
Hit any key to stop autoboot:  0
mmc0 is current device
SD/MMC found on device 0
221 bytes read in 149 ms (1000 Bytes/s)
Importing environment from mmc (uEnv.txt)...
Checking if uenvcmd is set ...
Running default loadzimage ...
MMC0: Data error with command 18 (status 0xf0302020)!
 ** ext4fs_devread read error - block
=>


I couldn't find anywhere what "ext4fs_devread read error - block"
means. Found message origin in ext4fs_devread() function in u-boot
source after some time but I really can't get my head around on what
it means just by reading code. I suspect it doesn't like block sizes
or something, not sure.

So I changed second partition to ext2 (instead of ext4) an changed env
parameters to instruct uboot that it is ext2 partition, nothing
changed.

Then I changed source header file include/configs/mx23_olinuxino.h and
removed #define CONFIG_CMD_EXT4 from it hoping it will remove ext4
support. I also changed hardcoded env parameters in same file from
mmcrootfstype=ext4 to mmcrootfstype=ext2.
Recompiled u-boot, dd it to sd card, rinse and repeat, got exactly the
same response on console you see above.

I give up for today after 3 hours of battling with it.

I plan to make 3 partitions: amtrak, vfat (for kernel) and ext4 (for
rootfs). But if ext4fs_devread persists to complain (and I apparently
haven't removed it from code) I don't think it would work either.

What is going on?
Can anyone give me some pointers what to do next?

Thanks,
Nidal.