docs

README.md

@@ -1,2 +1,36 @@
 # counter
 
+## Preparation
+
+
+Update:
+
+```
+apt update
+apt upgrade
+apt autoremove
+```
+
+
+Purge everything not required:
+
+```
+apt purge triggerhappy bluez wpasupplicant modemmanager avahi-daemon
+apt autoremove
+```
+
+Disable Bluetooth and WiFi at boot, put these lines in `/boot/firmware/config.txt`:
+
+```
+dtoverlay=disable-wifi
+dtoverlay=disable-bt
+```
+
+Install build chain and kernel headers:
+
+```
+apt install build-essential raspberrypi-kernel-headers git
+```
+
+
+