Currently, I am working on secondary UART boot loader using interrupt redirection method. Secondary Bootloader will be on FLASH starting from 0x203000 . I do not find such design elegant as it introduces delays and dependency on boot loader code. NXP library does not have API for NVIC remap ( FLASH <->RAM) as it looks they are using it themselves for ROM boot loader. ( if you see datasheet they mentioned that user is not allowed to use 32 bytes at start address of RAM).
Unfortunately PN7462 is Cortex-M0, along with above restrictions, there are not many options to design secondary boot loader.
I figured out PN7462 NXP is providing USB file system based ROM boot loader and SWD based FW upload; both are not useful.
- Would it be possible to get ROM boot loader based on UART instead of default USB file system based?
- Would it be possible to get a full access to ROM boot loader firmware ( FLASH to RAM ) so I can modify it as per our need.
- Any other alternate suggestion.