Stefnas,
Try regenerating the /boot/initrd-xxx.img with update-initramfs -u command, and then generate new uInitrd with mkimage command. Watch serial console if you have one connected, for any abnormal activities during rootfs mounting.
Try regenerating the /boot/initrd-xxx.img with update-initramfs -u command, and then generate new uInitrd with mkimage command. Watch serial console if you have one connected, for any abnormal activities during rootfs mounting.