update picocalc_helloworld/README.md

Code/picocalc_helloworld/README.md

@@ -11,6 +11,38 @@ cmake ..
 make  
 ```
 
-## Notes
+## How to Upload UF2 
+
+Uploading a UF2 file to the Raspberry Pi Pico on a Linux system is straightforward. Here’s how you can do it:
+
+### Step 1: Prepare Your Raspberry Pi Pico
+Enter Bootloader Mode:
+
+- Hold down the BOOTSEL button on your Pico.
+- While holding the button, connect the Pico to your Linux PC via USB.
+- Release the BOOTSEL button.
+- Check If the Pico Is Recognized:
+
+Your Pico should appear as a mass storage device named RPI-RP2.
+
+Verify using the following command:
+
+```bash
+lsblk
+```
+
+You should see a new device (e.g., /media/$USER/RPI-RP2 or /run/media/$USER/RPI-RP2).
+
+### Step 2: Copy the UF2 File to the Pico
+```
+cp your_firmware.uf2 /media/$USER/RPI-RP2/
+```
+
+### Step 3: Run it
+On PicoCalc, the default serial port of the Pico is the USB Type-C port, not its built-in Micro USB port.  
+So here is the standard running procedures: 
+
+- Unplug the pico from Micro-USB cable
+- Plug the pico via USB Type-C
+- Press Power On on Top of the PicoCalc
 
- On PicoCalc, the default serial port of the Pico is the USB Type-C port, not its built-in Micro USB port.