There is no firmware called Bistro OTSM. It appears to be a customized version of Flintrock’s Bistro HD.
As for differences, the names make it seem like the two are very similar, since it’s just “Bistro” and “Bistro HD”. But they only actually share a few lines of code. If I understand correctly, Flintrock tried to make the user interface very close to the original, but the underlying code differences are so large that it would be a good idea to test the firmware very thoroughly on a prototype of the light.
I haven’t really used Bistro HD much, since it never really worked correctly on any drivers I tried, but I can at least say I already see at least one UI difference between the diagram and what’s documented in Flintrock’s thread. Menu items 3 and 4 are swapped. It’s also likely that the number and details of the mode groups are different, and the manual really should have a list of what the mode groups are.
The difference is about 4000 to 7000 lines of code, depending on which parts are measured. For reference, the original Bistro is only about 1000 lines total. So it’s probably easier to list what they have in common, instead of what’s different: They share a similar user interface, and a few scattered stanzas of code.
As far as I’m aware, Bistro HD has only been used by a few people. This light will be the first time it has been used at a larger scale.
About OTC (original) vs OTSM (HD), the difference is:
- OTC (Off Time Capacitor) measures the voltage of a capacitor to determine how long the button was pressed. The driver fully shuts off at each button press, and boots fresh each time the light turns on. The button timing may vary with temperature though, since this uses the analog decay rate of the hardware as a way to measure time. Requires a bleeder resistor when a lighted tailcap is attached.
- OTSM (Off Time Sleep Mode) keeps the driver running for a few seconds during each button press, using the control chip’s internal timer to measure time. When power is restored, it continues from where it left off, without rebooting. Timing is much more consistent, but the chance of bugs increases since the driver doesn’t reset its state as often.
Yes, this is required by the license. The exact code shipped on the light needs to be provided.
“Mostly untouched” means it’s modified, and counts as a derivative version. GPLv3 sections 5 and 6 apply, “Conveying Modified Source Versions” and “Conveying Non-Source Forms”. Ideally, the license terms would be resolved in the manual, so the retailers would not have to care about the license. If the manual doesn’t include the right information though, retailers will have to carry the relevant information on their product pages.
But it’s not standard Bistro, not a standard Bistro driver, etc. It’s different hardware with different firmware.
The information may be in other threads somewhere, but it’s not here. The people running the project need exact, specific details… not a suggestion to look it up themselves and make guesses about which information is relevant.