***************
  Important !

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This new release of the U-Boot for the Tonga2 platform incorporates some
important changes that change the behaviour of U-Boot and can thus prevent
your board from starting up properly.

Please read the following *very* carefully.


Summary of changes
------------------

1. Usage of dynamic NAND partitions

2. Usage of NAND OOB marker to mark the offset position of the U-Boot
   environment

3. New LCD splash screen support

4. Reconfigurable ethernet MAC address


Changes in detail
-----------------

The following commands can only be performed with the new U-Boot release
booted on the board, either from RAM or NAND!

1. Usage of dynamic NAND partitions

To enable the use of the new dynamic NAND partition layout first a bad block
check needs to be performed:

	Tonga2> nand bad

After that execute

	Tonga2> dynpart

This initializes a default set of partitions. You can inspect the new table
using

	Tonga2> mtdpart

The MTD partitions become part of the U-Boot environment so you need to
perform step 2 (below) too.


2. Usage of NAND OOB marker to mark the offset position of the U-Boot
   environment

To enable the dynamic U-Boot environment performa the following command:

	Tonga2> nand env.oob set u-boot_env

The new environment information now needs to be saved to the NAND:

	Tonga2> saveenv


3. New LCD splash screen support

See the "Developers Manual TongARM" for more details.


4. Reconfigurable ethernet MAC address

The ethernet MAC address can now be changed in the U-Boot environment and is
automatically taken up by the kernel after startup. Set the MAC as follows:

	Tonga2> setenv ethaddr <valid-MAC>
	Tonga2> saveenv


Updating U-Boot
---------------

To Update anything in NAND flash the appropriate flash pages need to be
erased first. Erasing the pages also erases additional info in the
respective OOB blocks.
This also means that when the U-Boot is updated and in the process the
first NAND page is erased also the additional OOB U-Boot environment
information is erased and needs to be reset.
So in order to update U-Boot the following steps should be performed in this
order, for example loading the new U-Boot from tftp:

	Tonga2> tftpboot u-boot_nand_tonga2.bin
	Tonga2> nand erase u-boot
	Tonga2> nand write 0x40600000 u-boot
	Tonga2> nand env.oob set u-boot_env