You didn’t mention that you wanted to use SWD...
if you boards have Lpc-link2 on board, the you could program the JLink image (using lpcscrypt) and then use Jflash or jflash-lite - but you need to check the license as you may need to purchase the license (or not - I don’t know)
Flashmagic doesn't look like it can program that part? It appears to want the bootloader running on a serial port or USB port.
The dev board has what is essentially a LPC Link2 on it connected to the SWD interface of the 55S16.
Maybe I'm wrong, but it doesn't look like FlashMagic knows about JTAG/SWD interfaces on most parts....
You didn’t mention that you wanted to use SWD...
if you boards have Lpc-link2 on board, the you could program the JLink image (using lpcscrypt) and then use Jflash or jflash-lite - but you need to check the license as you may need to purchase the license (or not - I don’t know)