====== Flashing Olimex STM32-H103 using a Raspberry Pi ======
If you want to flash an Olimex STM32-H103, you don't actually need an expensive JTAG cable. The expensive JTAG cable was suggested by GNUK's README [(gnuk_readme)]. Well, I decided to buy a STM32-H103 to store my OpenPGP master key, using GNUK. This is possibly the cheapest option to obtain a OpenPGP smartcard. STM32-H103 is available on Amazon for £14 [([[https://www.amazon.co.uk/HEADER-BOARD-STM32F103-STM32-H103-OLIMEX/dp/B00AQNYM0U|HEADER BOARD FOR STM32F103 STM32-H103 By OLIMEX]])].

**It might be possible to read the STM32-H103's ROM content back into the Raspberry Pi**. I haven't personally tried it yet. I know the ROM is read-locked if you follow the flashing process above. However, the rumour says that is is fairly easy to do. So using a USB smartcard may not deter GCHQ / NSA from extracting your private key! I don't actually know if this is safer than storing your private key on an encrypted USB drive. However if you use a GNUK device, it is safer than storing your private key on the actual computer, and it is more convenient to use the private key than having to re-import it from a USB drive. 

===== Pinouts =====
You need to connect the two devices together following the two diagrams below:
<columns 100% - ->

==== Raspberry Pi JTAG using GPIO pins====
{{:public:rasperry_pi_jtag_pinout.png}}
<newcolumn>

==== STM32-H103 JTAG connector ====
{{:public:stm32_h103_jtag_pinout.gif}}
Note: nTRST connects to TRST on Raspberry Pi. [([[https://www.olimex.com/Products/ARM/ST/STM32-H103/resources/STM32-H103.pdf|STM32-H103 manual]])]
</columns>

===== Starting OpenOCD =====
<code bash>
sudo openocd -f interface/raspberrypi-native.cfg -f board/olimex_stm32_h103.cfg
</code>

===== Flashing STM32-H103 =====
<code>
telnet localhost 4444
reset halt
stm32f1x unlock 0
reset halt
flash erase_sector 0 0 127
flash erase_check 0
flash write_image erase gnuk.elf
verify_image gnuk.elf
stm32f1x lock 0
reset
shutdown
</code>

Note: You need to shutdown OpenOCD before using the GNUK device. 

[(gnuk_readme> "Q7: How much does it cost? A7: Olimex STM32-H103 plus ARM-USB-TINY-H cost 70 Euro or so.", [[https://anonscm.debian.org/cgit/gnuk/gnuk/gnuk.git/tree/README | GNUK Readme]])]