Adding information to the pfnVector table in order to support Secondary Bootloader

[rickvention2]

Dear all,

I am trying to make a secondary bootloader working on the NXP LPC55sXX series as described in the application note AN12327.

In order to do this, I have to add some information, an image header, to the created binary. The application note and corresponding example software describes how to add this in the pfn_Vectors table in which the interrupt handlers are defined.

I have tried adding this to the startup files in modules/hal/nxp/mcux/mcux-sdk/devices/LPC55S69, but it seems that these files are not actually used during compilation.
My next attempt was to copy the startup file to the application code and add

CONFIG_GEN_ISR_TABLES=y
CONFIG_GEN_IRQ_VECTOR_TABLE=n

but I get an error that there are multiple definitions of 'g_pfnVectors' so these vector tables are somehow somewhere still generated.

It is possible to add or overrule the vector tables in zephyr?

Kind regards,
Rick