Hi viskr,
Thank you for your response.
I managed to somehow get both channels detected by my PC after removing the EEPROM. It could be that the EEPROM was faulty.
I have also tried reading the user manual for lpc17xx (http://www.nxp.com/documents/user_manual/UM10360.pdf), but being a newbie to this, I have no idea how to “communicate with the bootloader”? Do I use Hyperterminal to send the “?” and if I do so, how do I send a program which activates the main crystal, since flashing it would require another tool (eg. Flash Magic)?