Hi !
I latest errata for LPC55S69 I can see :
"
5.1 ROM bootloader updated to provide API functionality for entry to ISP
mode
ISP.1: Devices with date code 2101 (yyww) and ROM patch version (T1.1.5), the ROM
bootloader will be updated to provide an API (runBootloader API) for the user application
to enter the ISP mode based on the designated ISP interface mode.
"
So basically this kind of ROM is only possible to have at beginning of the next year .
Regards,
Eugene