stm32loader.py fails with a .bin compiled on my machine

I've cloned the Espruino repository with the intention of contributing to the JavaScript implementation (in as far as I can wrap my head around C). I've got an Espruino board, so I'm running make with ESPRUINO_1V3=1.

I am on commit e4677650181132e9f883df9fbfeb4d4d3d60d3e9 when I'm doing all this. My machine is running Ubuntu 12.04 and I've installed all the compiler bits as far as I'm aware. (gcc, arm-none-eabi-gcc, and another one which name escapes me right now.)

My full make command:

ESPRUINO_1V3=1 BOARDNAME=1 make

I haven't exported any other env variables prior to running make.

Make exits with these last few lines, and an exit code of 0 (I think):

LD espruino_1v54_espruino_1r3.elf
GEN espruino_1v54_espruino_1r3.lst
GEN espruino_1v54_espruino_1r3.bin
bash scripts/check_size.sh espruino_1v54_espruino_1r3.bin
PASS - size of 214252 is under 215040 bytes 

Here's a full dump of make's output.

Then, I'm running the loader:

BOOT0=1 BOOT1=0 python scripts/stm32loader.py -k -p /dev/ttyACM0 -evw espruino_1v54_espruino_1r3.bin

Which outputs:

Reading data from espruino_1v54_espruino_1r3.bin
Traceback (most recent call last):
  File "scripts/stm32loader.py", line 525, in <module>
    bootversion = cmd.cmdGet()
  File "scripts/stm32loader.py", line 140, in cmdGet
    if self.cmdGeneric(0x00):
  File "scripts/stm32loader.py", line 137, in cmdGeneric
    return self._wait_for_ack(hex(cmd))
  File "scripts/stm32loader.py", line 101, in _wait_for_ack
    raise CmdException("Unrecognised response 0x%x to %s" % (ask, info))
__main__.CmdException: Unrecognised response 0x72 to 0x0

Is there something wrong with the build, or the problem purely in loading it onto the board? I'd appreciate any pointers.