pi@raspberrypi:~/tomu-bootloader/openocd $ cat almost_there.out
Open On-Chip Debugger 0.10.0+dev-00001-g0ecee83 (2017-01-23-19:52)
Licensed under GNU GPL v2
For bug reports, read
	http://openocd.org/doc/doxygen/bugs.html
BCM2835 GPIO nums: swclk = 25, swdio = 24
adapter speed: 1000 kHz
cortex_m reset_config sysresetreq
Info : BCM2835 GPIO JTAG/SWD bitbang driver
Info : SWD only mode enabled (specify tck, tms, tdi and tdo gpios to add JTAG mode)
Info : clock speed 1006 kHz
Info : SWD DPIDR 0x0bc11477
Info : efm32hg309.cpu: hardware has 0 breakpoints, 0 watchpoints
    TargetName         Type       Endian TapName            State
--  ------------------ ---------- ------ ------------------ ------------
 0* efm32hg309.cpu     cortex_m   little efm32hg309.cpu     reset
Error: JTAG failure 7
Info : SWD DPIDR 0x0bc11477
Error: JTAG failure 7
Info : SWD DPIDR 0x0bc11477
target halted due to debug-request, current mode: Thread
xPSR: 00000000 pc: 0xfffffffe msp: 0xfffffffc
Error: JTAG failure 7
Info : SWD DPIDR 0x0bc11477
target halted due to debug-request, current mode: Thread
xPSR: 0x01000000 pc: 0xfffffffe msp: 0xfffffffc
** Programming Started **
auto erase enabled
Info : detected part: EFM32 Happy Gecko - Rev: 135
Info : flash size = 64kbytes
Info : flash page size = 1024bytes
Info : SWD DPIDR 0x0bc11477
Error: Failed to read memory at 0x400c000c
Error: Failed to erase page 6
Info : SWD DPIDR 0x0bc11477
Error: Failed to write memory at 0x400c003c
Info : SWD DPIDR 0x0bc11477
Error: Failed to write memory at 0x100001c8
Error: JTAG failure 7
Info : SWD DPIDR 0x0bc11477
Error: error writing to flash at address 0x00000000 at offset 0x00000000
auto erase enabled
detected part: EFM32 Happy Gecko - Rev: 135
flash size = 64kbytes
flash page size = 1024bytes
SWD DPIDR 0x0bc11477
Failed to read memory at 0x400c000c
Failed to erase page 6
SWD DPIDR 0x0bc11477
Failed to write memory at 0x400c003c
SWD DPIDR 0x0bc11477
Failed to write memory at 0x100001c8
JTAG failure 7
SWD DPIDR 0x0bc11477
error writing to flash at address 0x00000000 at offset 0x00000000