Updated: Dec 8, 2020
I upgraded my VL1-m to firmware version by by replacing the EPROMs. See the pictures and description. The instruction is from Dennis Normer's Vl1 website. http://enlightenedsystems.com/vl/VL1PACKS.HTM#Version
Version 2 EPROMS, Voices, & Upgrade Instructions
New VL synths are equipped with the Version 2 firmware and voices, although Version 1 voice disks can be obtained and used. Beware, though, since a dealer may have a VL synth that sat on the shelf and has not been upgraded to Version 2. For those who own a Version 1 VL1, a very strong case can be made for upgrading to Version 2. Assuming that you payed about $2000 for your VL1-m (street price), the $200 (or less) cost to upgrade is small. The benefits are significant. This technology is in its infancy, and you can use every engineering improvement that they can make! To wit:
1) Quite a few of the voices have been improved. Notable improvements have been made, for example, in the trumpet, ethnic guitar, tenor sax, and recorder voices. This involves improved voicing and new elements, not just parameter tweaks. A number of the more odious Version 1 elements no longer exist.The new Excitation model (decay from pulse excitation) can be used in editing, and the new ethnic guitar voices, for example, use it.
2) The new Modulation Effects in Version 2 are Chorus, Phaser, Symphonic, Celeste, Distortion + Flanger, and Distortion + Wah. As with the Reverb effects, all of these effects are well done. The Chorus effect will find a lot of use, and I particularly like the Phaser, Symphonic, and Celeste effects. With the Phaser you can, for example, set the Feedback Gain and Wet/Dry Balance down from their wild levels to something in the range of 35% each to get an interesting evolving timbre change during held notes. The Distortion effects are probably aimed at the guitar voices, but could be used on others, if you like that sort of thing.
3) New parameters and extended or finer-grained parameter settings are available in Version 2 on almost all editing screens.
4) Version 2 allows keyboard splits with different elements for each hand. They have a dynamic way of implementing the split that follows your hand, without using a fixed split point.
5) Ver 2 brings a bunch of new breath noise types that are easy to select to get just the right breath noise for your favorite voice. Note that these breath noises are not just attack chiff, but are modeled according to the actual sound of a real musical instrument, so they may show up during sustain or decay, they may vary with breath pressure, may combine with pitch components (e.g. sax, flute, clarinet), and so on. This is not chump chiff!
6)The Mixing screen (the heart of the resonant model) has two new types of tap settings.
7) 30 new microtunings have been added, including Scottish highland bagpipe tuning, various Arabic tunings, Phrygian, Thai, African, etc.
That seems like quite a bit of inducement to me. The most important part, though, is the improved voices. They are making steady progress on getting more good, really playable voices, and eliminating the bad voices. One of the advantages of buying a programmable music box is that you can buy software (plus firmware) upgrades at modest prices. Quite a bit of engineering has been shoe-horned into a couple of EPROM chips and a floppy disk.
Version 2 EPROM Installation Instructions
These instructions apply to the VL1-m (rackmount), with the differences for the VL1 keyboard described farther below. It's not too tough if you follow certain guidelines. You might want to do this on the kitchen table where your floor isn't carpeted. Get a medium-small phillips-head screwdriver, a small slot-head screwdriver, and the VL1-m box on the table, and touch your sink fawcet before you start, to ground out any static electricity that you may have been carrying. Unscrew all of the screws holding the top/back sheet metal cover to the base/front, leaving alone the ones that don't go through the outer cover. There are about 20 of them, all the same. Don't lose any. Pull the cover off and eyeball the units guts. The digital circuit board is at the top rear, with the battery and EPROMs prominently visible in the middle of the board. I left my battery alone, but that's where it is if you ever need to replace it. Observe that each of the two EPROMs has a notch on one end, and make sure that you keep the orientation the same as you see. Notice also that both old and new EPROMs have serial numbers printed on top. You've got to replace the 'high' chip with the 'high' upgrade; consult the sheet that they are sending out with the upgrades now on which chip is hi/lo. The left and right units in each pair differ only in one digit. I believe one side had a '3' and the other had a '4' in the 'unique digit position' of the serial numbers. Use the small slot-head screwdriver to carefully pry up each end of just one of the original EPROMS. Pry with the screwdriver until you can pull it out with your fingers. Observe the polarity of the notch and the unique digit, and select the matching new EPROM. Check the width between the two rows of pins. If they are too wide to fit the socket, carefully bend them all together on each side on a flat surface (the table). So far no one has had to bend the pins. When they all line up just right above the socket, with the notch at the correct end, push it firmly into the socket. When pushing the chip into the socket, it is a bit nicer if you support the circuit board on the bottom with your other hand, to avoid flexing it too much. Do the same with the other chip. Replace the cover, but not all of the screws. After plugging the VL1 back in, watch the display during boot to make sure that it looks sanitary. The boot display will say 'Version 2' temporarily. If you get the chips reversed it will not boot, but no harm is done. Just reverse the high and low chip (keeping the notch at the same end). If all looks normal, congratulations! You are the proud owner of Version 2 of the latest, greatest music synthesis technology to commercially arrive on the planet! When you calm down, replace all screws, load the Version 2 VL1 main voice set, go into 'Utility/System/Breath Mode' and make sure it is 'BC/WX', and go to it!