Wrong MBED_ROM_START adress for Portenta H7

[Flydroid]

Description of defect

Compiling code for the Portenta H7 with the Arduino bootloader expects the code to start at mbed_rom_start=0x08040000.
The current targets.json this value is set to 0x08000000

mbed-os/targets/targets.json

Line 3481 in 99cb885

"mbed_rom_start": "0x08000000",

Target(s) affected by this defect ?

Portenta H7 M7

Toolchain(s) (name and version) displaying this defect ?

gccarmnoneeabi@1.50401.211104
through platformio

What version of Mbed-os are you using (tag or sha) ?

mbed-os 6.9.0
"bare-metal" profile

What version(s) of tools are you using. List all that apply (E.g. mbed-cli)

Platformio
platformio-stm32 @ 15.2.0
framework-mbed @ 6.60900.210318 (6.9.0)

How is this defect reproduced ?

flashing the blinky script will not run without mbed_rom_start=0x08040000 changed in target.json in the framework-mbed folder in platformio/packages
(i think there is an mbed_app.json overwrite which can be used instead of editing target.json but It went under in today's debugging)

[mbedmain]

@Flydroid thank you for raising this issue.Please take a look at the following comments:

What toolchain(s) are you using?

NOTE: If there are fields which are not applicable then please just add 'n/a' or 'None'. This indicates to us that at least all the fields have been considered.
Please update the issue header with the missing information.

[Flydroid]

@mbedmain I have updated the issue description

This article got me on the right lead https://link.medium.com/nWas4OpNDob

[jeromecoutant]

@facchinm

[facchinm]

Hi @Flydroid ,
we decided to keep the "project" start at the beginning of the flash for the following use cases:

• users that don't need a bootloader
• users that want to write a bootloader

Changing that filed in your own mbed_app.json is trivial https://github.com/arduino/ArduinoCore-mbed/blob/master/variants/PORTENTA_H7_M7/conf/mbed_app.json#L17 so I think that right way to handle this is by writing some better documentation 😉
@sebromero

[Flydroid]

Alright, the mbed_app.json config works!
Better documentation is always appriciated!

I will also open an issue with platformio so the mbed framework gets added to the portenta H7.

[sebromero]

@facchinm @Flydroid we have a small piece of documentation on this here: https://docs.arduino.cc/tutorials/portenta-h7/por-ard-bl#memory-layout
Does that work or do you think we need to add more information?

[sebromero]

@facchinm @Flydroid I added the information about where to adjust the start address here: arduino/docs-content#119