Merge branch 'main' of https://github.com/sq2ips/m20-custom-firmware

README.md

@@ -91,6 +91,19 @@ Hardware requirements:
 - 5 male to female goldpin jumper wires
 - A computer with Linux or Windows
 
+## Recomended hardware modifications
+## Load resistor
+If you have a sonde with new GPS module, there is a additional parallel 62 Ohm resistor added at the output of the voltage converter, all it does it drawing ~53mA from the line and converting it to heat. I have no idea why it was added, removing it does not make the power supply unstable or anything like that, maybe it was added for draining the battery quicker. You can safely remove this resistor to save some energy from the battery.
+This is the resistor:
+
+![alt text](https://github.com/sq2ips/m20-custom-firmware/blob/main/img/rezystor.jpg?raw=true)
+
+Thermal camera image:
+
+![alt text](https://github.com/sq2ips/m20-custom-firmware/blob/main/img/termo.jpg?raw=true)
+
+(Image from SP9AOB)
+
 ## Downloading code
 First you need to obtain the code, you can do it with `git`:
 ```bash
@@ -233,6 +246,6 @@ After it finishes you can flash the built firmware:
 ```
 After it finishes your sonde should now work with the new firmware.
 ## Flashing on Windows with ST-Link utility
-Fisrt [download the utility](https://www.st.com/en/development-tools/stsw-link004.html#get-software), extract, install and run it.
+Fisrt [download the utility](https://www.st.com/en/development-tools/stsw-link004.html#get-software), extract, install and run it. Connect to the ST-Link and open the binary compiled file with .bin extension. Then go to Target -> Flash & Verify, check that the adress is set to 0x80000000 and the flash.
 
 # Debuging (TODO)