doc: boards: amlogic: update documentation for Khadas VIM2

Improve documentation.

Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Link: https://lore.kernel.org/r/20230320114609.930145-10-christianshewitt@gmail.com
[narmstrong: fixed doc build]
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>

doc/board/amlogic/khadas-vim2.rst

@@ -1,25 +1,25 @@
 .. SPDX-License-Identifier: GPL-2.0+
 
-U-Boot for Khadas VIM2
-=======================
+U-Boot for Khadas VIM2 (S912)
+=============================
 
-Khadas VIM2 is an Open Source DIY Box manufactured by Shenzhen Wesion
-Technology Co., Ltd with the following specifications:
+Khadas VIM2 is a Single Board Computer manufactured by Shenzhen Wesion Technology Co. Ltd
+with the following specifications:
 
  - Amlogic S912 ARM Cortex-A53 octo-core SoC @ 1.5GHz
  - ARM Mali T860 GPU
- - 2/3GB DDR4 SDRAM
+ - 2GB/3GB DDR4 SDRAM
+ - 16GB/32GB/64GB eMMC
  - 10/100/1000 Ethernet
  - HDMI 2.0 4K/60Hz display
  - 40-pin GPIO header
  - 2 x USB 2.0 Host, 1 x USB 2.0 Type-C OTG
- - 16GB/32GB/64GB eMMC
  - 2MB SPI Flash
  - microSD
  - SDIO Wifi Module, Bluetooth
  - Two channels IR receiver
 
-U-Boot compilation
+U-Boot Compilation
 ------------------
 
 .. code-block:: bash
@@ -28,14 +28,21 @@ U-Boot compilation
     $ make khadas-vim2_defconfig
     $ make
 
-Image creation
---------------
+U-Boot Signing with Pre-Built FIP repo
+--------------------------------------
 
-For simplified usage, pleaser refer to :doc:`pre-generated-fip` with codename `khadas-vim2`
+.. code-block:: bash
 
-Amlogic doesn't provide sources for the firmware and for tools needed
-to create the bootloader image, so it is necessary to obtain them from
-the git tree published by the board vendor:
+    $ git clone https://github.com/LibreELEC/amlogic-boot-fip --depth=1
+    $ cd amlogic-boot-fip
+    $ mkdir my-output-dir
+    $ ./build-fip.sh khadas-vim2 /path/to/u-boot/u-boot.bin my-output-dir
+
+U-Boot Manual Signing
+---------------------
+
+Amlogic does not provide sources for the firmware and tools needed to create a bootloader
+image so it is necessary to obtain binaries from sources published by the board vendor:
 
 .. code-block:: bash
 
@@ -50,7 +57,7 @@ the git tree published by the board vendor:
     $ make
     $ export FIPDIR=$PWD/fip
 
-Go back to mainline U-Boot source tree then :
+Go back to the mainline U-Boot source tree then:
 
 .. code-block:: bash
 
@@ -65,40 +72,40 @@ Go back to mainline U-Boot source tree then :
     $ cp u-boot.bin fip/bl33.bin
 
     $ $FIPDIR/blx_fix.sh \
-    	fip/bl30.bin \
-    	fip/zero_tmp \
-    	fip/bl30_zero.bin \
-    	fip/bl301.bin \
-    	fip/bl301_zero.bin \
-    	fip/bl30_new.bin \
-    	bl30
+              fip/bl30.bin \
+              fip/zero_tmp \
+              fip/bl30_zero.bin \
+              fip/bl301.bin \
+              fip/bl301_zero.bin \
+              fip/bl30_new.bin \
+              bl30
 
     $ python $FIPDIR/acs_tool.pyc fip/bl2.bin fip/bl2_acs.bin fip/acs.bin 0
 
     $ $FIPDIR/blx_fix.sh \
-    	fip/bl2_acs.bin \
-    	fip/zero_tmp \
-    	fip/bl2_zero.bin \
-    	fip/bl21.bin \
-    	fip/bl21_zero.bin \
-    	fip/bl2_new.bin \
-    	bl2
+              fip/bl2_acs.bin \
+              fip/zero_tmp \
+              fip/bl2_zero.bin \
+              fip/bl21.bin \
+              fip/bl21_zero.bin \
+              fip/bl2_new.bin \
+              bl2
 
     $ $FIPDIR/gxl/aml_encrypt_gxl --bl3enc --input fip/bl30_new.bin
     $ $FIPDIR/gxl/aml_encrypt_gxl --bl3enc --input fip/bl31.img
     $ $FIPDIR/gxl/aml_encrypt_gxl --bl3enc --input fip/bl33.bin
     $ $FIPDIR/gxl/aml_encrypt_gxl --bl2sig --input fip/bl2_new.bin --output fip/bl2.n.bin.sig
     $ $FIPDIR/gxl/aml_encrypt_gxl --bootmk \
-    		--output fip/u-boot.bin \
-    		--bl2 fip/bl2.n.bin.sig \
-    		--bl30 fip/bl30_new.bin.enc \
-    		--bl31 fip/bl31.img.enc \
-    		--bl33 fip/bl33.bin.enc
+                                  --output fip/u-boot.bin \
+                                  --bl2 fip/bl2.n.bin.sig \
+                                  --bl30 fip/bl30_new.bin.enc \
+                                  --bl31 fip/bl31.img.enc \
+                                  --bl33 fip/bl33.bin.enc
 
-and then write the image to SD with:
+Then write U-Boot to SD or eMMC with:
 
 .. code-block:: bash
 
     $ DEV=/dev/your_sd_device
     $ dd if=fip/u-boot.bin.sd.bin of=$DEV conv=fsync,notrunc bs=512 skip=1 seek=1
-    $ dd if=fip/u-boot.bin.sd.bin of=$DEV conv=fsync,notrunc bs=1 count=444
+    $ dd if=fip/u-boot.bin.sd.bin of=$DEV conv=fsync,notrunc bs=1 count=440