tweak softdevice hex file

[marklander]

Hi,

first of all i know that this is not a "good question", but my hacker side is trying to... tweak hex file of softdevice 113 to fit my low memory footprint.

I mean s113 jumps to 0x1c000 in the normal case, but i see that final address of hex file is about around 0x1b400. I am trying to recover some space tweaking hex file references to my new jump address 0x1b800.

 At the moment it seems that sofdevice enable is not working? But is there a possibility to do that?

Sorry for the weird question, but it would be helpful to have that bunch of bytea for my application.

[marklander]

Adding one note:

I tried moving to 0x1D000 the tweaked address and seems working!

Maybe is there any sanity check inside SD code that blocks not aligned address in some way?

[Vidar Berg]

Hello,

It is possible to change the application start address in the softdevice binary as you have discovered, and while it will likely work just fine, we cannot guarantee it won't have side effects since it is not something we test for. The start address must be aligned to a 4096 byte page boundary. Otherwise, you will encounter problems when updating the application image through DFU.

marklander said:

Maybe is there any sanity check inside SD code that blocks not aligned address in some way?

I have not confirmed this, but it seems like the most likely explanation. 

[marklander]

I discovered that there was an issue on my side, softdevice boots fine also from 0x1b800...

Thanks for support!