board/olpc: document flashing the JFFS2 image

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
This commit is contained in:
Lubomir Rintel 2020-06-17 12:49:23 +02:00 committed by Thomas Petazzoni
parent 5417a6e588
commit f61f3e932c

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@ -9,10 +9,13 @@ Supported models
* OLPC XO-1
The original NS Geode based OLPC laptop, uses the x86 architecture.
Can be booted either from an internal MTD device formatted with JFFS2
or from a FAT or EXT4 partition on a SD card or a USB flash stick.
* OLPC XO-7.5
The ARM-based laptop. Needs a recent enough firmware to provide a good
enough flattened device tree to the kernel.
enough flattened device tree to the kernel. Can be from a FAT or EXT4
partition on a internal eMMC, a SD card or a USB flash stick.
Configure and build
===================
@ -59,20 +62,37 @@ to update the firmware:
ok flash ext:\q4e00ja.rom \ Flash the "q4e00ja.rom" from the SD card
ok flash u:\q4e00ja.rom \ Flash the "q4e00ja.rom" from USB stick
Create the bootable media
=========================
Create the bootable SD card or USB flash stick
==============================================
When the build is finished, the resulting image file will be called
"sdcard.img". It can be written directly to a SD-card or and USB flash stick.
When the build is finished, an image file called "sdcard.img" will be created.
It is suitable for writing directly to a SD card, USB flash stick or (on a
XO-1.75) the internal eMMC flash.
Please double check that you're using the right device (e.g. with "lsblk"
command). Doing the following will DESTROY ALL DATA that's currently on the
media.
Before writing the image, please double check that you're using the right
device (e.g. with "lsblk" command). Doing the following will DESTROY ALL DATA
that's currently on the media.
# cat output/images/sdcard.img >/dev/<device>
Flashing the JFFS2 image (XO-1 only)
====================================
Unlike XO-1.75, the internal NAND flash on XO-1 is accessed without a
FTL and needs a flash-friendly filesystem. A build configured for XO-1
creates a file named "root.jffs2" that can be written to it.
One way to write it is from the Open Firmware prompt. First, partition
and format a USB flash disk with a FAT file system and place the
"root.jffs2" file onto it. Then power on the machine, enter the
Open Firmware port by pressing the ESC key and run the following:
ok patch noop ?open-crcs copy-nand \ Disable CRC check
ok copy-nand u:\root.jffs2
Booting the machine
===================
Once your machine is unlocked, it will automatically boot from your media
wherever it will detect it attached to the USB bus or the SD card slot.
wherever it will detect it attached to the USB bus or the SD card slot,
otherwise it will proceed booting from the internal flash.