[RESEND PATCH 2/3] Nokia RX-51: Update documentation about flashing

[Pali Rohár]

This change contains update for doc/README.nokia_rx51 documentation file
with information how to load U-Boot image to device RAM without need to
flash it and also how to flash it into OneNAND via 0xFFFF flasher.

Signed-off-by: Pali Rohár <pali at kernel.org>
---
 doc/README.nokia_rx51 | 45 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/doc/README.nokia_rx51 b/doc/README.nokia_rx51
index 1be077514f03..e739b02088ea 100644
--- a/doc/README.nokia_rx51
+++ b/doc/README.nokia_rx51
@@ -22,6 +22,51 @@ following repository:
 
   https://github.com/pali/u-boot-maemo
 
+To generate combined.bin image from u-boot.bin and kernel.bin (either uImage
+or zImage) use:
+
+  sh u-boot-gen-combined u-boot.bin kernel.bin combined.bin
+
+Original Maemo Fremantle PR1.3 zImage kernel binary is available at:
+
+  http://repository.maemo.org/pool/maemo5.0/free/k/kernel/kernel_2.6.28-20103103+0m5_armel.deb
+
+To unpack it (from DEB/AR, TAR and FIASCO) call commands:
+
+  ar x kernel_2.6.28-20103103+0m5_armel.deb data.tar.gz
+  tar -O -xf data.tar.gz ./boot/zImage-2.6.28-20103103+0m5.fiasco > kernel_2.6.28-20103103+0m5.fiasco
+  0xFFFF -M kernel_2.6.28-20103103+0m5.fiasco -u
+
+Flashed image must start with 2 kB "NOLO!img" header which contains size of
+the image. Header consist of bytes "NOLO!img\x02\x00\x00\x00\x00\x00\x00\x00"
+followed by 4 byte little endian size of the image and rest of the 2 kB header
+are just zero bytes.
+
+Nokia proprietary flasher and also open source 0xFFFF flasher automatically
+prepend required "NOLO!img" header and both applications expect that image
+does not contain "NOLO!img" header. Adding "NOLO!img" header is required
+only in case using "nandwrite" tool for flashing.
+
+Open source 0xFFFF flasher is available in following repository:
+
+  https://github.com/pali/0xFFFF
+
+It is possible to load u-boot.bin via USB to N900 RAM and boot it without
+need to flashing it. Via 0xFFFF running at host PC it is done:
+
+  0xFFFF -m u-boot.bin -l -b
+
+0xFFFF support also flashing kernel image either via USB or directly on
+N900 device. Flashing u-boot/kernel/combined image is done as:
+
+  0xFFFF -m combined.bin -f
+
+Via 0xFFFF is possible to generate also standard flashable image in Nokia
+FIASCO format which contains metadata information like device identification
+(RX-51) and version string (v2021.04):
+
+  0xFFFF -m RX-51:v2021.04:kernel:u-boot.bin -g u-boot.fiasco
+
 There is support for hardware watchdog. Hardware watchdog is started by
 NOLO so u-boot must kick watchdog to prevent reboot device (but not very
 often, max every 2 seconds). There is also support for framebuffer display
-- 
2.20.1