Hi Zoran,
You could take a look at application note AN10744 “Ethernet secondary ISP bootloader”, especially on section 3.4 “Modifying the user application”:
http://host.lpcware.com/system/files/AN10744_0.pdf
On AN10759 you may find helpful related information:
http://www.po-star.com/public/uploads/20120326115107_161.pdf
Hope this will be useful for you.
Best regards!
/Carlos
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------