Cubieboard: after first try can't read the SD card, no boot

[imrehg]

Hi, I'm trying to set up a Cubieboard according the instructions. Looks like the system cannot boot, because after successfully loading the boot script, u-boot cannot read the SD card anymore. Here's the relevant log using the debug serial:

$this->bbcode_second_pass_code('', '<snip>
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
Found U-Boot script /boot/boot.scr
805 bytes read in 135 ms (4.9 KiB/s)
## Executing script at 43100000
** ext4fs_devread read error - block
** Can't read partition table on 0:0 **
** Invalid partition 1 **
SCRIPT FAILED: continuing...
scanning bus for devices...
Found 0 device(s).
<snip>
')

Checking this out manually, if I stop the autoboot, and do a file system listing then it works, but loading the kernel fails, and after that the file system listing fails too:

$this->bbcode_second_pass_code('', 'Hit any key to stop autoboot: 0
sunxi# ext4ls mmc 0:1 /boot/
<DIR> 4096 .
<DIR> 4096 ..
4958328 zImage
<DIR> 20480 dtbs
805 boot.scr
sunxi# ext4load mmc 0:1 0x42000000 /boot/zImage
** ext4fs_devread read error - block
sunxi# ext4ls mmc 0:1 /boot/
** Can't read partition table on 0:0 **
** Invalid partition 1 **
')

The SD card that I use (Sandisk 16GB) run the official Debian system without any problem, booted, used it fine.

Any idea what can be wrong here?