I tried a lot of things, but to make flash2advance work I had to buy an old laptop with a lpt port. Unfortunately the new adapters work on other "addresses" and there is no way to convert them. Also check the cable, it should be DB25M - DB25M. That is 25 pins to each other. New lpt cables usually do not make 25 to 25. Moreover, according to the developers, the cable should be no longer than one meter. You should have EPP/ECP mode settings in your laptop's bios. In the settings of Windows itself (idk about Mac), the LPT should sit at address: 0378-037F. Given all the hassle (buying a laptop, soldering the right cable) it is easier to buy an ez FLASH Omega.
Btw parallel to USB adapter definitely not suitable.