This tutorial is not about soldering, and flashing SPI chips. Who can solder SPI flash, and USB port, he knows what to do. Backup u-boot, art partitions and so on.
I like to mod routers, but i don't like to rebuild every time openwrt when new release or trunk comes out.
pros:
- router uses official openwrt build
-
- i can use official kmods when they suddenly needed
-
- i think there is more but can't remember right now
cons:
- loose some space versus custom build
Ok .Lets assume we have WR841N V13. We already solder USB(WR841N V13 USB Mod) port and changed SPI flash to 16mb. We flashed chip with u-boot and install openwrt( https://github.com/lede-project/source/commit/24043a0d2e01b9843c0dc529205b3b0bc7ecbbf9)
But USB is disabled in official openwrt release, and still 8m is accessible.
First of all
git clone https://git.openwrt.org/openwrt/openwrt.git/ myrepack
cd myrepack
git checkout openwrt-18.06
./scripts/feeds update -a
./scripts/feeds install -a
Then we have to add new flash layout. I think layouts is bad, why just not use direct values for every router.
Edit tools/firmware-utils/src/mktplinkfw2.c to look like this
.kernel_ep = 0x80000000,
.rootfs_ofs = 0x140000,
}, {
.id = "16Mmtk",
.fw_max_len = 0xfa0000,
.kernel_la = 0x80000000,
.kernel_ep = 0x80000000,
.rootfs_ofs = 0x140000,
}, {
.id = "8MLmtk",
.fw_max_len = 0x7b0000,
Next
cp target/linux/ramips/dts/TL-WR841NV13.dts target/linux/ramips/dts/TL-WR841NV13.dts.my
Change target/linux/ramips/dts/TL-WR841NV13.dts.my first line
#include "TPLINK-8M.dtsi" to #include "TPLINK-16M.dtsi"
Then create cp target/linux/ramips/dts/TPLINK-8M.dtsi target/linux/ramips/dts/TPLINK-16M.dtsi with this inside
#include "mt7628an.dtsi"
/ {
chosen {
bootargs = "console=ttyS0,115200";
};
memory@0 {
device_type = "memory";
reg = <0x0 0x4000000>;
};
};
&spi0 {
status = "okay";
m25p80@0 {
#address-cells = <1>;
#size-cells = <1>;
compatible = "jedec,spi-nor";
reg = <0>;
spi-max-frequency = <10000000>;
m25p,chunked-io = <32>;
partition@0 {
label = "boot";
reg = <0x0 0x20000>;
read-only;
};
partition@20000 {
label = "firmware";
reg = <0x20000 0xfa0000>;
};
factory: partition@fc0000 {
label = "factory";
reg = <0xfc0000 0x30000>;
read-only;
};
};
};
&ehci {
status = "okay";
};
&ohci {
status = "okay";
};
&wmac {
status = "okay";
mtd-mac-address = <&factory 0xf100>;
mediatek,mtd-eeprom = <&factory 0x20000>;
};
ðernet {
mtd-mac-address = <&factory 0xf100>;
mediatek,portmap = "llllw";
};
Now we need a bunch of host binaries to extract official release, build dts inject dtb to kernel and pack everything back
Here is my script, but you can run line by line
cat megarepack.sh
#!/bin/bash -x
make="make -j 9"
echo "CONFIG_TARGET_ramips=y" > .config
echo "CONFIG_TARGET_ramips_mt76x8=y" >> .config
echo "CONFIG_TARGET_ramips_mt76x8_DEVICE_tl-wr841n-v13=y" >> .config
make defconfig
make dirclean
#make prepare
$make tools/firmware-utils/compile
$make tools/lzma/compile
$make tools/patch-image/compile
$make toolchain/gcc/final/compile
$make target/linux/compile
$make toolchain/kernel-headers/compile
sed -i 's@$(eval $(call BuildPackage,fwtool))@#$(eval $(call BuildPackage,fwtool))@' package/system/fwtool/Makefile
$make package/fwtool/compile
The result must be binaries in ls staging_dir/host/bin/{fwtool,lzma,mktplinkfw2,patch-dtb}
and ls staging_dir/toolchain-mipsel_24kc_gcc-7.3.0_musl/bin/mipsel-openwrt-linux-musl-c++
Now the trickiest part, dtc can be compiled in kernel. Here is the source build_dir/toolchain-mipsel_24kc_gcc-7.3.0_musl/linux/scripts/dtc but i don't know how, so i simply install dtc in centos 7
yum install dtc
Lets compile our dts to dtb. Here is my script
cat build_dtb.sh
#!/bin/bash -x
STAGING_DIR=`pwd` staging_dir/toolchain-mipsel_24kc_gcc-7.3.0_musl/bin/mipsel-openwrt-linux-musl-cpp -nostdinc -x assembler-with-cpp \
-Ibuild_dir/toolchain-mipsel_24kc_gcc-7.3.0_musl/linux/arch/mips/boot/dts \
-Ibuild_dir/toolchain-mipsel_24kc_gcc-7.3.0_musl/linux/include \
-undef -D__DTS__ -o tl-wr841n-v13-kernel.bin.dtb.tmp target/linux/ramips/dts/TL-WR841NV13.dts.my
dtc -O dtb --phandle both \
-i build_dir/toolchain-mipsel_24kc_gcc-7.3.0_musl/linux/arch/mips/boot/dts \
-o tl-wr841n-v13-kernel.bin.dtb tl-wr841n-v13-kernel.bin.dtb.tmp
And here we are, we got tl-wr841n-v13-kernel.bin.dtb with usb and new layout partitions activated. Now we need to unpack openwrt release to kernel and rootfs. Inject dtb to kernel, and pack everything back.
Here is how i'm doing it
wget "https://downloads.openwrt.org/releases/18.06.1/targets/ramips/mt76x8/openwrt-18.06.1-ramips-mt76x8-tl-wr841n-v13-squashfs-sysupgrade.bin"
And then a little script $1 is openwrt-18.06.1-ramips-mt76x8-tl-wr841n-v13-squashfs-sysupgrade.bin
#!/bin/bash -x
#extract kernel and rootfs
staging_dir/host/bin/mktplinkfw2 -x -i $1
#unzip kernel
staging_dir/host/bin/lzma d $1-kernel $1-kernel-decoded
#inject our dtb
staging_dir/host/bin/patch-dtb $1-kernel-decoded tl-wr841n-v13-kernel.bin.dtb
#zip kernel back
staging_dir/host/bin/lzma e $1-kernel-decoded $1-kernel-decoded.new
#create sysupgrade image
staging_dir/host/bin//mktplinkfw2 -H 0x08410013 -W 0x268 -w 0x13 -F "16Mmtk" -T 3 -V "ver. 2.0" -a 0x4 -j -k $1-kernel-decoded.new -r $1-rootfs -o openwrt-ramips-mt76x8-tl-wr841n-v13-squashfs-sysupgrade.bin.new -s -e
#make it sysupgradable
echo '{ "supported_devices":["tl-wr841n-v13"], "version": { "dist": "OpenWrt", "version": "18.06.1", "revision": "r7258-5eb055306f", "board": "ramips" } }' | staging_dir/host/bin/fwtool -I - openwrt-ramips-mt76x8-tl-wr841n-v13-squashfs-sysupgrade.bin.new
openwrt-ramips-mt76x8-tl-wr841n-v13-squashfs-sysupgrade.bin.new Is our new sysupgradable image with USB support and 16mb flash layout. Now you can just sysupgrade it. Then restore the art partition with
insmod mtd-rw i_want_a_brick=1
mtd write art.bin factory
Now you can fast repack any release or trunk snapshot for you moded tl-wr841n-v13
This is draft. Or this knowledge will be lost 