From Technologic Systems Manuals

An XNAND2 formatted NAND device will work on supported products with any bootrom date, whether or not the bootrom supports XNAND2.  However, devices can only be booted from the XNAND technology that their bootrom supports. An XNAND2 formatted NAND cannot be booted from a bootrom that only supports XNAND1 and vice versa. This allows for application support of XNAND2, regardless of bootrom support, but only if NAND is not the boot media. Because of this, it is important to update all programming and production processes to support XNAND2. For other production preparation processes that do not re-image the entire device, it is still important to confirm the production process is using the XNAND2 nandctl binary dated October 2016 or later. The following section provides the necessary information to update an existing XNAND1 image with the new XNAND2 nandctl software.

The latest nandctl binary is compatible with both XNAND1 and XNAND2; however it will assume that disk initialization will be targeted at XNAND2 support and it is not possible to force XNAND1 formatting. Because of this, the bootrom should be updated to be compatible with XNAND2 before using '--xnandinit' against a NAND device using the latest nandctl binary. TS-BOOTROMs with a date after October 2016 are compatible with and able to boot XNAND2 devices.

This update will walk through the steps of updating the nandctl binary contained in a customized production image. These steps are not necessary when using our stock image, only if your production process is using an SD or NAND image that has been based on any of our previous shipping images. Note that both SD and NAND images should be updated to properly support XNAND2 in all situations.

To prepare this update, a workstation running linux is necessary, either in a virtual machine or native install. From the workstation, open a terminal window and copy your original production image file to a local working directory (this is done to limit working on production used images).  This file will be referenced as diskimg.dd in the following instructions. The latest XNAND2 compatible nandctl binary (link to download is at the top of this section) should also be downloaded in the same working directory.

Next, run the following command:

sudo fdisk -l diskimg.dd

This will produce output like the following:

Disk diskimg.dd: 268 MB, 268435456 bytes
255 heads, 63 sectors/track, 32 cylinders, total 524288 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

      Device Boot      Start         End      Blocks   Id  System
diskimg.dd1                1        5119        2559+  da  Non-FS data
diskimg.dd2             5120       10239        2560   da  Non-FS data
diskimg.dd3            10240      524287      257024   83  Linux

The above is the partition table of an XNAND disk. An image for an SD card will have 4 partitions rather than 3, but the same basic layout. The necessary information is the start sector of the second partition with the Id of "da," and the "Sector size" listed above the partition table. In this case it is partition 2 in which the start block is 5120 and the Sector size is 512. Multiply the two numbers to obtain the necessary offset:  5120 * 512 = 2621440.

Next, the initrd partition from the disk image file is mounted to a folder created in the working directory:

mkdir mnt
sudo mount -orw,loop,offset=$((5120*512)) diskimg.dd mnt/

The new XNAND2 nandctl binary is copied to the mounted folder structure

cp nandctl mnt/sbin/nandctl

The disk image can be unmounted and renamed as needed:

sudo umount mnt
mv diskimg.dd diskimg-xnand2.dd