@magpern the instructions on openhardware.io state that the Molgan must be battery powered while programming:

Well, then I can confirm that you don't have to power the Molgan from batteries just for programming. Burning the bootloader works fine with just power from the ISP port and programming it through FTDI works fine if power comes from the FTDI.

What I found wierd is that the atmega328 had power, the radio had power, it wrote debug messages to the FTDI - when powered through the FTDI, it send radio messages etc, but it just did not receive messages.
Messages where not received until I supplied power to the + / - pads (battery pads).

I did read the instructions on openhardware.io, but I didn't follow then to the t. :)

"Remove the batteries and connect a standard FTDI serial cable (the ones used to program an Arduino Pro-Mini) to the FTDI connector of the add-on PCB. Replace the batteries and plug the FTDI cable in your PC."

I don't understand why, power is power... but apparently power is different.
So, for future builders, if you run this, you know what I did.

Need to head to IKEA and get some more Molgans!!

Edit: I have assembled all the stuff and the node is kind of working. It presents itself to the gateway perfectly. What does not work is the motion sensor. The pin is always high. When I pull it down manually and release it again, the node sends its message.
I have removed the light sensor and R17. I have replaced R11 with a 1k resistor because that was the smallest one I had. Could this be a problem?

Edit: Ok, found the problem. Seems like I have accidentally unsoldered R2 when I removed the light sensor. From your pictures I found out, that there has to be a 470k resistor. Now it works. :)

"C:\Program Files (x86)\Arduino\hardware\tools\avr\bin\avrdude.exe" -C "C:\Program Files (x86)\Arduino\hardware\tools\avr\etc\avrdude.conf" -c usbasp -p m328p -b 115200 -P usb -V -U flash:w:ATmegaBOOT_168_atmega328_pro_8MHz.hex

After this I am not able to flash sketches via the Arduino IDE. Any ideas?

Today I burned a bootloader (with the right fuses) to the new board and uploaded the securityPersonalizer and the molgan sketch via serial... and everything is working! It takes some (re)tries to get the signing up and running but after ~2 seconds the molgan board showed up in the gateway log. Now I'll only have to connect the new board to the molgan pcb and hope that everything still works.

I still don't know why it wasn't working before though. I have some other chips that I programmed via ISP and they work well with signing too...

1. Your device is not properly personalized
2. Your key has been overwritten in eeprom by some other part of your sketch during runtime
3. Your key has been erased by stack growth (unlikely since it very much look like eeprom reset value)

You can test the various scenarios by moving your newly added print to various places in the backend. For instance, adding it just after the value is fetched from eeprom in the init function of the backend would tell you if the value is bad in eeprom or is erased in ram at a later stage.

// Feed "message" to HMAC calculator
	DEBUG_SIGNING_PRINTBUF(F("HMAC key debug: "), _signing_hmac_key, 32);
	_signing_sha256.initHmac(_signing_hmac_key,32); // Set the key to use

The output of that is

HMAC key debug: FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

which is definitly not my HMAC key!

PS Changing the timeout did not change this.

• list item22.602 Bytes (73%) of memory
• list itemglobal variables 56% of dynamic memory

How do you change the timeout? Quick googling only turned up requests to make it configurable...