Hi there,

we need to flash an encrypted application to the qspi attached NOR flash of our microcontroller and debug it with Ozone. At runtime, the application will be decrypted transparently in the background on-the-fly by a peripheral of the MCU. For the writing of the unencrypted application we use SEGGERs Open Flashloader and it this works, but doing the encryption in Open Flashloader while writing to the NOR flash does not work at all.

Our new plan now is to encrypt the application before giving it to Open Flashloader, but we still need to be able to use Ozone for debugging. For this I need some background knowledge regarding how Ozone is using JLink for downloading the application the the MCU.

Question: Is there a way, to make Ozone use an encrypted .bin for downloading, but using an unencrypted .elf for debugging? I suppose when we encrypt the complete .elf file Ozone won't be able to debug anymore.

Any further suggestions on how to achieve our goal would be much appreciated.

Best regards
Paul

Hello Nino,

thanks a lot for your reply, that sounds good and I will try it.
Just to be clear here: You mean in the TargetDownload() routine in the .jdbug file, I shall refer a unencrypted .elf file as well, not the .bin file, correct?

Addition: It seems, that when I point to a .bin file in .jdbug (TargetDownload("<path>/.bin", <adress>), Ozone ignores the bin and downloads the content of the .elf file which is denoted in the Ozone project file with File.Open ("<path-to-elf-file>") in function OnProjectLoad(void){...}

Best regards
Paul

Hello Nino,

unfortunately Ozone does not use for download the .bin I specify in .jdebug file. Here is what I do:

• Using Ozone v3.10d together with JLink V6.62a
  
• Ozone project file (<myApp>.jdebug) contains path to .elf file ( File.Open("<path>/<myApp>.elf") in function OnProjectLoad(){...}) as well as the path to the .bin file ( Target.LoadMemory("<path>/<myApp>.bin", BaseAdress).
  
• The bin file is basically the same as the bin part within the .elf file, but I changed a few bytes at the beginning and the end for testing purposes (see next step)
  
• After having done "Download & Reset Programm" with Ozone using the .jdebug file mentioned above, I open a Memory View window in Ozone and export the content of the memory (QSPI attached external flash) beginning at BaseAdress (parameter used in Target.LoadMemory(...) function, see above).
  
• When I compare the binary data of the memory export and the .bin file indicated in Target.LoadMemory(), the binary data is not the same, i.e. I don't see the modified bytes mentioned above. So obviously Ozone did not download the .bin file denoted in TargetLoadMemory(...).
  
• Because we flash the application not to the internal flash of the MCU but to an external flash attached via qspi, we have to use SEGGERs OpenFlashLoader. But think this should not make a difference for our use of Target.LoadMemory
  

Am I doing sth. wrong here?

Many thanks in advance
Paul

Hello Nino,

sure, I'll attach .jdebug and J-Link log file to this post.

I tried the export of the external flash memory via J-Link + savebin as you described, still the test.bin (see .jdebug) does not match the savebin export.

Best regards
Paul