added udev rule

firmware/Readme.md

@@ -47,6 +47,39 @@ sudo apt update
 sudo apt install libusb-1.0-0-dev libudev-dev
 ```
 
+### 1.3. Fix the USB permissions issue
+Add a udev rule for WCH-Link / minichlink.
+
+Before creating the rule, verify the USB vendor and product IDs match your device:
+```Bash
+lsusb
+```
+Example output:
+```Bash
+Bus 001 Device 005: ID 1a86:8010 QinHeng Electronics WCH-Link
+```
+Make sure:
+
+- `1a86` matches `idVendor`
+- `8010` matches `idProduct`
+
+If your device reports different IDs, use those values in the rule below.
+
+Create:
+```Bash
+sudo nano /etc/udev/rules.d/99-wch.rules
+```
+Add:
+```Bash
+SUBSYSTEM=="usb", ATTR{idVendor}=="1a86", ATTR{idProduct}=="8010", MODE="0666"
+```
+Then reload:
+```Bash
+sudo udevadm control --reload-rules
+sudo udevadm trigger
+```
+Unplug/replug the programmer.
+
 ## 2. Install Flashing Tool (minichlink)
 Clone the ch32fun repository and build minichlink:
 ```Bash