Hello,

I am using the J-LINK GDB server V7.98a for downloading and debugging my firmware on a Nordic nrf9160.

Recently I added a flash area for storing persistent data in the firmware. This data is located in the area 0x000f8000-0x000f9fff.

When I download my full application, this persistent area gets erased. This is an excerpt of the log I see in the GDB server log (you can see my attempts to define which areas to erase and to enable the RWM feature):

Received monitor command: exec erase 0x00000000-0x0007FFFF
Executed erase 0x00000000-0x0007FFFF
Received monitor command: exec erase 0x00FF8108-0x00FF8388
Executed erase 0x00FF8108-0x00FF8388
Received monitor command: exec SetFlashDLNoRMWThreshold = 0xFFFFFFFF
Executed SetFlashDLNoRMWThreshold = 0xFFFFFFFF
Received monitor command: reset 0
Resets core & peripherals via SYSRESETREQ & VECTRESET bit.
Downloading 16128 bytes @ address 0x00000000
Downloading 11676 bytes @ address 0x00003F00
Downloading 16080 bytes @ address 0x00008000
Downloading 16112 bytes @ address 0x0000BED0
Downloading 576 bytes @ address 0x0000FDC0
Downloading 1458 bytes @ address 0x00010000
Downloading 16080 bytes @ address 0x00018000
Downloading 16112 bytes @ address 0x0001BED0
Downloading 576 bytes @ address 0x0001FDC0
Downloading 1458 bytes @ address 0x00020000
Downloading 16096 bytes @ address 0x00028000
Downloading 16160 bytes @ address 0x0002BEE0
Downloading 512 bytes @ address 0x0002FE00
Downloading 16096 bytes @ address 0x00030000
Downloading 16000 bytes @ address 0x00033EE0
Downloading 16032 bytes @ address 0x00037D60
Downloading 15888 bytes @ address 0x0003BC00
Downloading 1520 bytes @ address 0x0003FA10
Downloading 16016 bytes @ address 0x00040000
Downloading 16016 bytes @ address 0x00043E90
Downloading 16064 bytes @ address 0x00047D20
Downloading 16000 bytes @ address 0x0004BBE0
Downloading 1440 bytes @ address 0x0004FA60
Downloading 15984 bytes @ address 0x00050000
Downloading 16080 bytes @ address 0x00053E70
Downloading 16096 bytes @ address 0x00057D40
Downloading 16096 bytes @ address 0x0005BC20
Downloading 1280 bytes @ address 0x0005FB00
Downloading 16064 bytes @ address 0x00060000
Downloading 16048 bytes @ address 0x00063EC0
Downloading 16096 bytes @ address 0x00067D70
Downloading 16080 bytes @ address 0x0006BC50
Downloading 1248 bytes @ address 0x0006FB20
Downloading 16192 bytes @ address 0x00070000
Downloading 16352 bytes @ address 0x00073F40
Downloading 16288 bytes @ address 0x00077F20
Downloading 10967 bytes @ address 0x0007BEC0
Downloading 80 bytes @ address 0x00FF8130

When I download a sample application (which does not write the 80 bytes to the address 0x00FF8130) the persistent data remains intact:


Received monitor command: exec erase 0x00000000-0x0007FFFF
Executed erase 0x00000000-0x0007FFFF
Received monitor command: exec erase 0x00FF8108-0x00FF8388
Executed erase 0x00FF8108-0x00FF8388
Received monitor command: exec SetFlashDLNoRMWThreshold = 0xFFFFFFFF
Executed SetFlashDLNoRMWThreshold = 0xFFFFFFFF
Received monitor command: reset 0
Resets core & peripherals via SYSRESETREQ & VECTRESET bit.
Downloading 588 bytes @ address 0x00000000
Downloading 8664 bytes @ address 0x00000260
Downloading 13836 bytes @ address 0x00002440
Downloading 312 bytes @ address 0x00007C00
Downloading 16080 bytes @ address 0x00008000
Downloading 13768 bytes @ address 0x0000BED0

How can I ensure that the persistent area is not erased during a firmware download?

Thank you
Stefan

Add "memory.region add ro 0x000f8000 0x2000" does not help... The persistent data is erased after the download.

Received monitor command: exec memory.region add ro 0x000f8000 0x2000
Executed memory.region add ro 0x000f8000 0x2000
Received monitor command: reset 0
Resets core & peripherals via SYSRESETREQ & VECTRESET bit.
Downloading 16128 bytes @ address 0x00000000
Downloading 11676 bytes @ address 0x00003F00
Downloading 16080 bytes @ address 0x00008000
Downloading 16112 bytes @ address 0x0000BED0
Downloading 576 bytes @ address 0x0000FDC0
Downloading 1458 bytes @ address 0x00010000
Downloading 16080 bytes @ address 0x00018000

Ok, I am not getting it: According to the log in localhost:19080/flash.htm the area with persistent data is not touched at all... Where the heck is the stored data?

I close this thread as I found a solution for the issue. I am using the Cortex-M plugin in a docker container to connect to the GDB server running natively on my host. In order to "keep" the settings in the device I added the following to the launch.json (specific for the Cortex-M Plugin):

"overrideLaunchCommands": [
"monitor reset 0",
"dump memory ./settings.bin 0x000f8000 0x000fffff",
"-target-download",
"restore ./settings.bin binary 0x000f8000",
"monitor reset 0"
],

This dumps the settings area to a file and pushes it back onto the device after the target-download has erased the area.