Flashing U-Boot
--------------------------------
-There are two options: the original bootloader in NAND can be replaced with
-u-boot, or u-boot can be stored on the NOR flash without erasing
-the delivered bootloader.
+U-boot should be stored on the NOR flash.
+
The boot storage can be select using the switches on the personality board
(SW1-SW2) and on the DEBUG board (SW4-SW10).
-The second option is to be preferred if you have not a JTAG debugger.
If something goes wrong flashing the bootloader, it is always possible to
recover the board booting from the other device.
-Replacing the bootloader on the NAND
---------------------------------------
-To replace RedBoot with U-Boot, the easy way is to do this in linux.
-Start the kernel with the suggested options. Make sure to have set the
-mtdparts exactly as described, because this matches the layout on the
-mx35pdk.
-
-You should see in your boot log the following entries for the NAND
-flash:
-
-5 cmdlinepart partitions found on MTD device mxc_nand
-Creating 5 MTD partitions on "mxc_nand":
-0x000000000000-0x000000100000 : "boot"
-0x000000100000-0x000000600000 : "linux"
-0x000000600000-0x000006600000 : "root"
-0x000006600000-0x000006e00000 : "cfg"
-0x000006e00000-0x000080000000 : "user"
-
-You can use the utilities flash_eraseall and nandwrite to put
-u-boot on the NAND. The bootloader is marked as "boot", and 1MB is
-reserved. If everything is correct, this partition is accessed as
-/dev/mtd4. However, check if it is correct with "cat /proc/mtd" and
-get the device node from the partition name:
-
-$ cat /proc/mtd | grep boot
-
-I suggest you try the utilities on a different partition to be sure
-if everything works correctly. If not, and you remove RedBoot, you have to
-reinstall it using the ATK tool as suggested by Freescale, or using a
-JTAG debugger.
-
-I report the versions of the utilities I used (they are provided with ELDK):
-
--bash-3.2# nandwrite --version
-nandwrite $Revision: 1.32 $
-
-flash_eraseall --version
-flash_eraseall $Revision: 1.22 $
-
-nandwrite reports a warning if the file to be saved is not sector aligned.
-This should have no consequences, but I preferred to pad u-boot.bin
-to get no problem at all.
-$ dd if=/dev/zero of=zeros bs=1 count=74800
-$ cat u-boot.bin zeros > u-boot-padded.bin
-
-To erase the partition:
-$ flash_eraseall /dev/mtd4
-
-Writing u-boot:
-
-$ nandwrite /dev/mtd4 u-boot-padded.bin
-
-Now U-Boot is stored on the booting partition.
-
-To boot from NAND, you have to select the switches as follows:
-
-Personality board
- SW2 1, 4, 5 on
- 2, 3, 6, 7, 8 off
- SW1 all off
-
-Debug Board:
- SW5 0
- SW6 0
- SW7 0
- SW8 1
- SW9 1
- SW10 0
-
-
Saving U-Boot in the NOR flash
---------------------------------
-The procedure to save in the NOR flash is quite the same as to write into the NAND.
-
Check the partition for boot in the NOR flash. Setting the mtdparts as reported,
the boot partition should be /dev/mtd0.