CTNandBoot

Sets Cubietruck (and now CubieBoard2 also) to allow Linux boot from NAND. Also can save and restore user NAND and also create the MBR and download partitions. See further down for details on these new features.

Fixing boot0, boot1.

One problem with CTs is that one has to run PhoenixSuit and download an image (e.g. Linaro) just to change some code so the CT to boot from NAND.

This program (called bootfix) will run on a CT (also i386 and probably other systems) and will change a target CT so it will boot from NAND. Only the 'hidden' NAND is changed. This means the user will have to load the accessible NAND (MBR and partitions) later, probably by booting from an SD card. If the NAND has already been setup, it won't be changed and the CT will boot automatically after the program has run.

The program requires some data files and all are included here. The executable 'bootfix' included here will run on a CT. Use 'make' to compile bootfix for other host machines.

To run this program, connect the target CT (must be in FEL mode), and then run ./bootfix and wait till finished (less than one minute). Most of the output is "URB xxxxxx" lines which relate to records in the original USB monitor file. There is a notes file that lists my notes about these records. Connecting a serial monitor to the target CT will provide more details.

Booting from NAND requires more files in the boot partition than when booting from SD card. For consistency, these extra files can be put in the SD card partition and will be ignored.

The required files are:
	/boot.axf
	/boot.ini
	/uEnv.txt
	/script.bin
	/uImage
	/linux/linux.ini
	/linux/u-boot.bin

uEnv.txt, script.bin, and uImage vary to suit the board and kernel.

With SD card boot, the bootloader is stored at sector 16 onwards. This bootloader uses uEnv.txt, script.bin, and uImage only.

With NAND boot, the bootloader runs boot.axf which uses boot.ini then /linux/linux.ini then runs /linux/u-boot.bin. This u-boot.bin uses uEnv.txt, script.bin, and uImage.

A skeleton boot partition is included. The script.bin and uImage files must be added. The uEnv.txt file will probably require customising.

Saving and restoring all NAND.

"./bootfix -r" will save all NAND to a file called NAND.DAT.
"./bootfix -r <file_id>" will save all NAND to the specified file.

"./bootfix -w" will load NAND from a file called NAND.DAT.
"./bootfix -w <file_id>" will load all NAND from the specified file.

Creating MBR and partitions.

Each partition to be created must exist as a file. When bootfix is run with the -i switch it checks the following list of files and details. Each partition entry is enclosed in quotes and contains the file name, start key, and size (sectors) for the partition. Each file will become a partition on the NAND device. The partition name is derived from the file name. The start key will be the greater of the specified key and the next available sector. The partition size will be the greater of the file size and the specified size.

Example: ./bootfix -i "/temp/bootloader 2048 0" "/temp/rootfs 0 0" "/temp/data 0 0"

bootfix will create the MBR then the three partitions (bootloader, rootfs, data).

2016-05-05 fix: Partitions are now aligned to super-blocks to avoid alignment error warnings when booting. This avoids the chance of affecting a partition when updating an adjacent partition.