I am not sure if I got it right.
The linker is only involved until the .elf file has been created.
If the question is to pad out the content of the .hex file so it is one
continuous block then it can be done with :
avr-objcopy -j .text -j .data -j .my_signature --gap-fill 0xFF -O ihex
prog.elf prog.hex
The gap-fill argument fills the blanks with a specific value (0xFF in this
case).
Cheers
Michael
> Am 2022-01-19 um 16:30 schrieb Jim Brain <br...@jbrain.com>:
>
> On 1/19/2022 7:13 AM, Michael Stocker wrote:
>> You are right.
>>
>> -Wl,--undefined=signature
>>
>> This will keep it in flash and not let the linker strip its value.
>> Also when preparing your .hex file for flashing you may need to explicitly
>> tell the sections you want.
>>
>> avr-objcopy -j .text -j .data -j .my_signature -O ihex prog.elf
>> prog.hex
>>
>> Cheers
>>
>> Michael
>>
> This may be a naive question, but is it possible to "place" the signature in
> a specific location in the resulting output file, padding the file to the
> required size to include the signature?
>
> Use case:
>
> One of the projects I utilize defines a 4 byte signature at the end of the
> AVR code space (top 4 bytes), and it checks that signature in the bootloader
> to see if an update on storage is newer than the one installed. Right now,
> the main developer has created a Perl script that pulls the resulting object
> file, padds it out, and puts the 4 bytes at the end. It would be nice to do
> all of that in the linker.
>
>
