I was using SDCC and GCC compiler and debugger for my x51 and AVR projects. Iguana Labs kindly provided protocol for their programmer(i could use serial port sniffer programs) on their website so I decided to write my own Linux version to upload hex files on the same platform as programming was taking place.
GUI was never a option for me because this program was made to be simple and efficient.During the development of program for microcontroller you need a fast I/O interface and fastest way to enter commands which you have to enter repeatedly is by using keyboard. The second reason at the time was that only machine in the house with free tty ports was old P166 debian machine without X server used as a house router/firewall. If you like GUI so much you can use my code and make GUI. After all code is licensed under GPL.
This program had and in a way still has very buggy interface I usually compiled this program with default settings for each project and never took time to create save/load settings from file. This software can (load/set/save) settings from file for different microcontrollers. Check Instructions / HOWTO use this software. One of the reasons was of course also unavailability of PG302 firmware.