Hi.
With the help of Bodhi, I was able to successfully boot Arch Linux from sd card using Davy Gravy's U-Boot.
I just followed Bodhi's instructions with few changes,
I will attach my changes on the bottom,
keep in mind that I tried different settings before success,
so it possible that I made some changes that I don't recall,
I recommend you to have a look at my whole U-Boot settings.
I've successfully flashed:
1. Davy Gravy's U-Boot from the original Pogoplug Linux.
2. Arch Linux U-Boot on Davy Gravy's U-Boot. EDIT: Wrong, didn't worked.
3. Davy Gravy's U-Boot on Arch Linux U-Boot. EDIT: No, didn't done it because 2 didn't worked, but it should work.
Although I documented all the steps I made,
somehow in all my tries some arguments needed to manually set again,
so I decided not to publish here a guide because I don't want users bricking their devices.
I had no success in reverting to stock Pogoplug U-Boot, so I didn't tried the process again on a clean machine.
Anyway you can follow my steps on Doozan's forums and look at my U-Boot settings.
Davy Gravy's U-Boot: http://forum.doozan.com/read.php?3,7477
Bodhi's Instructions: http://forum.doozan.com/read.php?3,7477,10982#msg-10982
My U-Boot printenv: http://pastebin.com/6bKSVPrQ
My changes:
$this->bbcode_second_pass_code('', 'usb_rootfstype=ext3
mmc_boot=mw 0x800000 0 1; ext2load mmc 0:1 0x00800000 /boot/uImage; if ext2load mmc 0:1 0x01100000 /boot/uInitrd; then bootm 0x800000 0x1100000; else bootm 0x800000; fi
mmc_bootcmd=mmc init; mmc init; run mmc_set_bootargs; run mmc_boot
mmc_root=/dev/mmcblk0p1
mmc_set_bootargs=setenv bootargs console=$console root=$mmc_root rootdelay=$usb_rootdelay rootfstype=$usb_rootfstype $mtdparts $usb_custom_params
')
I still like to be able to revert to stock firmware, I would love to get some hints on the matter.