Is't possible to change app start address from prebuild binary file?

[kaiwak]

Hi,
Usually we set FLASH_START macro to indicate application start address,
I do like to consult is't possible to change the FLASH_START from prebuild binary file without rebuild?

I'm trying to implement dual boot, that is, 2 different application are programed to 2 address of flash,
then boot to one of them depending on bootloader choice,

For example, app1 start from 0x27000, app2 start from 0x8d000,
I set FLASH_START=0x27000 for app1,
FLASH_START=0x8d000 for app2,
then build hex files and program them to flash.

That works but I need to decide application start address before compiling,
I hope the start address can be set by bootloader dynamically,
if application is programed to address of app1, set it to 0x27000, otherwise 0x8d000,
is't possible?

Thanks~

[Jørgen Holmefjord]

Hi,

It is possible to change the start address of the HEX-file using objcopy:

arm-none-eabi-objcopy --change-addresses <address> <input_file>.hex <output_file>.hex

However, I'm not sure if the application will work correctly if moved this way. You may try it out in your device.

Best regards,
Jørgen

[Jørgen Holmefjord]

Do both application use the softdevice? See this section in the documentation:

"For the SoftDevice to locate the application interrupt vectors, the application must define its interrupt vector table at the bottom of the Application Flash Region illustrated in Memory resource map. When the base address of the application code is directly after the top address of the SoftDevice, the code can be developed as a standard ARM Cortex -M4 application project with the compiler creating the interrupt vector table."