- (C) 2024 Sean.Hung <https://github.com/seanhungtw/belkin_rt1800_openwrt>
- Extraordinary is you improve yourself every day

# belkin_rt1800_openwrt
- A note for how to build a Openwrt image for RT1800 with MTK HNAT (23.05 only)
  - Original Openwrt doesn't support MTK HANT on MT7921 platform, immortalwrt has MTK HANT support on 5.10 kernel.
  - So, I porting the driver from immortalwrk and modify it, so it can running on 5.15 kernel and matches belkin rt1800 hardware
- RT1800 hardware info:
  - CPU: MT7621
  - Wi-Fi chip: MT7915D (DBDC)

- Refer: https://openwrt.org/docs/guide-developer/toolchain/beginners-build-guide
- if the MTK hnat work properly, you should see CPU usage is neraly zero when WAN => LAN traffic running in full speed (big tcp packet)
  - <img src='/readme_mt7621_cpu_wantolan.jpg' width='50%'>

## Get the code
```
git clone https://git.openwrt.org/openwrt/openwrt.git # or https://github.com/openwrt/openwrt.git
cd openwrt
git checkout v23.05.2
git checkout -b rt1800_23052
```
### Dwonload belkin_rt1800_openwrt/openwrt23 and paste it to the 23.05.2 sourcr code
just copy and paste, don't delete existed files in 23.05.2

### update feeds
```
./scripts/feeds update -a
./scripts/feeds install -a
```
### menuconfig
```
make menuconfig
#Select MediaTek Ralink MIPS => MT7621 based boards => Belkin RT1800

make defconfig
```
### build the image
```
make -j$thread
```
### Known issues

- Can't use DSA switch, rollback to swconfig (because we need to use MTK 7530 driver)
- wifi interface name is hardcoded in the dts, currently only support "phy0-ap0", "phy1-ap0", "phy0-ap1", "phy1-ap1", "phy0-sta0", "phy1-sta0"

## Trouble shooting

### git issue

you may want to set some git config to avoid git error

```
git config -l
git config --global http.postBuffer 1048576000
git config --global https.postBuffer 1048576000
git config --global http.lowSpeedLimit 0
git config --global http.lowSpeedTime 999999
```

### compile openwrt in WLS2

you need to disable windows PATH: or it will meet build errors
```
~/openwrt$ cat /etc/wsl.conf

[interop]

enabled = false

appendWindowsPath = false
```

## Notes of MTK board customization

### default /etc/config/network & eth nterface name (both openwrt 22 & 23)

you can configure interface name, mac here:
```
#file :target/linux/ramips/mt7621/base-files/etc/board.d/02_network

#for example
ucidef_set_interfaces_lan_wan "lan1, lan2, ..." "wan"
lan_mac="00:11:22:33:44:55"
wan_mac="00:11:22:33:44:56"
```
then it goes to the original Openwrt code to generate default /etc/config/network file:
```
package/base-files/files/bin/config_generate
```
### default wireless config flow
default the /etc/config wireless is empty, when system init, it will call 
```
/etc/init.d/network
```
then the network script will call
```
/sbin/wifi
```
the wifi script will include any file in the /lib/wifi

take rt1800 as example:
```
/lib/wifi/mac80211.sh
```
if the driver works, the ifname will be created in the following path:
```
root@OpenWrt:/# ls /sys/class/ieee80211/
phy0  phy1
```
the mac80211.sh will generate the /etc/config/wireless file according to phy0  phy1 data above