+### Reflashing Firmware ###
+
+To reflash the system firmware on ChaosKey, you first need to get the
+device into 'bootloader mode'. To do this, you must power-up ChaosKey
+with a jumper between GND and the Boot Loader Select pin.
+
+Open up ChaosKey by prying the case apart. There's no glue or screws,
+so a thin tool or fingernail should suffice to split the case into two
+pieces. Once you've opened it up, you'll find the inside that looks
+much like this:
+
+<img src="chaoskey-connector.svg">
+
+Connect a wire between the two red holes in the debug connector and
+then plug it in to your computer. It will appear as a USB modem device
+called AltosFlash with USB ID fffe:000a.
+
+Use the 'ao-usbload' program, which is part of the
+[AltOS repository](https://altusmetrum.org/AltOS/)
+and is packaged for Debian in the 'altos' package:
+
+ $ ao-usbload chaoskey-v1.0-*.elf
+