Don't complain; at least you're not a Mac user, who are the ones who're really screwed because they need to physically attach their drives to a x86 PC.
The standard course of action for Linux, FreeBSD, or anyone who uses x86 but not Windows is to use a DOS boot disk (or boot CD; there is a good DOS boot CD specially tailored for firmware flashing on >NIL:'s page at rpc1.org) and boot to DOS to flash their drive using TDB's DOS flasher.
NEC never made one. Liggy made one in his own time by re-writing and adapting DVRFlash (an unofficial flasher for Pioneer drives using fplscsi) for the NEC. Yes, it's possible to make a cross-platform flasher. Would you like to make one? Making flashers is a lot of work, and if there is a Windows flasher (and a DOS flasher), then the entire x86 segment is covered, and nobody wants to put in the extra work of developing a flasher. If you have what it takes, then please, be our guest.