@pinsh
These errors are completely normal besides this one:
EXT4-fs (mmcblkp0p4): unable to read superblock

And as you already mentioned - you know why it is shown. To fix it, you need to update your /etc/bootmenu.d/whatever-you-have-for-arch.item, check if both ITEM_DEVICE and ITEM_CMDLINE are correct. Then run "u-boot-update-bootmenu" in Maemo terminal. Check out the steps that were given in the link sent by ArchiMark and note that /dev/mmcblk0p* is the internal memory and /dev/mmcblk1p* is the SD card. And I hope you are sure that you are using ext4?