Content originally posted in LPCWare by goffi on Mon Feb 24 14:26:38 MST 2014
I don't know which version of iar you are using, but you should use FlashNXPLPC18xx_43xx_OnChip_X.mac (X=A or B depend which flash you need to program) or similar macro file in debugger->setup.
In debugger->download , enable "verify download" , "use flash loader" and " override default board". Don't use lpc43xx flash loader (don't ask me why, but doesn't works for me) and select FlashNXPLPC18xx_1024K.board . After this, click on edit and select the flash you want program.
I hope it will works also for you.