App note from NXP giving step by step guide on creating flash programming file for MDK and also using pre-compiled flash programming algorithm which can be used directly. Link here (PDF)
LPC546xx has external spi flash interface(SPIFI) which can R/W external flash with single/dual/quad mode. It also supports XIP mode which means code can be executed directly on spi flash. SPIFI greatly expands application’s code size, and makes it possible to store large data(image or even videos). However, downloading data into spi flash in development phase is always a troublesome problem, since different spi flash vendors have different command sets. Customers often meet the situation that original flash programming algorithm in MDK cannot fit their hardware, which causes downloading data incorrectly.