How to set nrf51 Read Back Protection using OpenOCD?

[Jerod]

Looking for the OpenOCD equivalent of ""nrfjprog --rbp all"

Looking at the commands for OpenOCD they have a "flash protect" command, but it doesn't appear that's quite the same thing (requests regions of flash).

Any assistance for a OpenOCD newbie would be appreciated!

[endnode]

Hi Jerod,

Simply write 0xFFFF00FF to UICR->RBCONF register which resides on address 0x100010004. To be precise you should read it out and mask with that value (to preserve PR0 register part on the least significant byte of the register in case it is used). Also make sure what endian OpenOCD use to code raw 32-bit hexadecimal values when writing to the memory. In the end reset the target and memory should be protected.

Btw. you can easily do this from within the FW code to be sure that you don't forget this in production and also note that nRF51 has major security hole in read-back protection and debugging interface so doing RBALL is rather cosmetic thing which saves you against people who cannot use Google search.

Cheers Jan

Edit 10-Feb-2017

Here is HEX file which writes RBALL to UICR->RBCONF on any nRF51 variant. It can be flashed by any tool including OpenOCD. Can be stripped down to single register write (with little bit of work with GCC tools or similar) but normally it isn't needed.

Cheers Jan

nrf51822_UICR_lock.hex

[Jerod]

Thanks. I was unaware of the security hole! I was trying to learn a little more about OpenOCD and nrf support to see how the two work together -- as the majority of guides seem to stick to the basic, wipe, program, reset capabilities.

[endnode]

Cool. Are you able to use single word write in OpenOCD and verify that it works? Could you then close the case or give me a feedback what's missing? Thx

[Jerod]

Technically, the question hasn't been answered; still looking for the way to do this in OpenOCD. I will hunt down the proper command(s) and post here before closing.

[endnode]

I'm adding HEX file to my answer which should solve your problem. I suppose you can flash HEX with OpenODC (e.g. by using "-i" option in "flash_nrf51822.py").

[Jerod]

Still not able to get us to a state of read back protected files.

Using OpenOCD, one cannot write your hex file after SoftDevice and Program are written.

Here is the command and output:

D:\OpenOCD\bin>openocd.exe -f ../scripts/interface/stlink-v2.cfg -f "C:\Program Files\GNU ARM Eclipse\OpenOCD\0.10.0-201701241841\scripts\target\nrf51.cfg" -s ..\share\openocd\scripts -c "init" -c "halt" -c "nrf51 mass_erase 0" -c "program sd.hex verify" -c "program myprogram.hex verify" -c "program nrf51822_UICR_lock.hex verify" -c "reset" -c "exit"

Open On-Chip Debugger 0.9.0 (2016-09-01) [https://github.com/sysprogs/openocd]

Licensed under GNU GPL v2

For bug reports, read

openocd.org/.../bugs.html

Info : auto-selecting first available session transport "hla_swd". To override use 'transport select '.

Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD

adapter speed: 1000 kHz

Info : Unable to match requested speed 1000 kHz, using 950 kHz

Info : Unable to match requested speed 1000 kHz, using 950 kHz

Info : clock speed 950 kHz

Info : STLINK v2 JTAG v23 API v2 SWIM v4 VID 0x0483 PID 0x3748

Info : using stlink api v2

Info : Target voltage: 3.172668

Info : nrf51.cpu: hardware has 4 breakpoints, 2 watchpoints

Info : nRF51822-QFAA(build code: E0) 256kB Flash

nrf51.cpu: target state: halted

target halted due to debug-request, current mode: Thread xPSR: 0xc1000000 pc: 0xfffffffe msp: 0xfffffffc

** Programming Started **

auto erase enabled

Info : Padding image section 0 with 2112 bytes

Warn : using fast async flash loader. This is currently supported

Warn : only with ST-Link and CMSIS-DAP. If you have issues, add

Warn : "set WORKAREASIZE 0" before sourcing nrf51.cfg to disable it

nrf51.cpu: target state: halted

target halted due to breakpoint, current mode: Thread

xPSR: 0x61000000 pc: 0x2000001e msp: 0xfffffffc

wrote 93184 bytes from file sd.hex in 4.006389s (22.714 KiB/s)

** Programming Finished **

** Verify Started **

nrf51.cpu: target state: halted

target halted due to breakpoint, current mode: Thread

xPSR: 0x61000000 pc: 0x2000002e msp: 0xfffffffc

nrf51.cpu: target state: halted

target halted due to breakpoint, current mode: Thread

xPSR: 0x61000000 pc: 0x2000002e msp: 0xfffffffc

verified 90328 bytes in 0.636024s (138.691 KiB/s)

** Verified OK **

nrf51.cpu: target state: halted

target halted due to debug-request, current mode: Thread

xPSR: 0xc1000000 pc: 0x000006d0 msp: 0x000007c0

** Programming Started **

auto erase enabled

Warn : using fast async flash loader. This is currently supported

Warn : only with ST-Link and CMSIS-DAP. If you have issues, add

Warn : "set WORKAREASIZE 0" before sourcing nrf51.cfg to disable it

nrf51.cpu: target state: halted

target halted due to breakpoint, current mode: Thread

xPSR: 0x61000000 pc: 0x2000001e msp: 0x000007c0

Warn : Adding extra erase range, 00000000 to 0x00000013

Warn : using fast async flash loader. This is currently supported

Warn : only with ST-Link and CMSIS-DAP. If you have issues, add

Warn : "set WORKAREASIZE 0" before sourcing nrf51.cfg to disable it

nrf51.cpu: target state: halted

target halted due to breakpoint, current mode: Thread

xPSR: 0x61000000 pc: 0x2000001e msp: 0x000007c0

wrote 14572 bytes from file myprogram.hex in 0.822974s (17.292 KiB/s)

** Programming Finished **

** Verify Started **

nrf51.cpu: target state: halted

target halted due to breakpoint, current mode: Thread

xPSR: 0x61000000 pc: 0x2000002e msp: 0x000007c0

verified 14252 bytes in 0.143640s (96.895 KiB/s)

** Verified OK **

nrf51.cpu: target state: halted

target halted due to debug-request, current mode: Thread

xPSR: 0xc1000000 pc: 0x000006d0 msp: 0x000007c0

** Programming Started **

auto erase enabled

Error: The chip was not pre-programmed with SoftDevice stack and UICR cannot be erased separately. Please issue mass erase before trying to write to this region

Error: failed erasing sectors 0 to 0

embedded:startup.tcl:454: Error: ** Programming Failed **

in procedure 'program'

in procedure 'program_error' called at file "embedded:startup.tcl", line 510

at file "embedded:startup.tcl", line 454