Hello, I am sorry that you had trouble with the beta. I double checked here, but the firmware doesn't enable downgrading. We have limited that to avoid compatibility issues with the latest hardware and earlier firmware versions. In fact, that is tied to the same reason we ask for serial numbers before we share firmware for upgrading. It allows us to verify compatibility and make sure there will not be issues. As our firmware gets more sophisticated in verifying versions we can hopefully make that more easily available.
I'm sorry, but i'm not really buying that. You had no problem to hand out a link to the beta firmware so that people can test it. Nowhere in that post did it say something like "This firmware is only suitable for units in the serial number / hardware revision range XXX to YYY, please do not apply to units outside thatt range". In the teardown videos there are resistor straps visible that set the revision of the unit. Did Rigol place them there just for fun, or can the firmware read out what they are set to? I would assume the latter, so the firmware should be able to differentiate.
If the firmware really can't make that distinction, then it is rather poorly designed when it comes to such stuff. Heck, even 50€ sat receivers can do it and tell you that some firmware file for another type, using the exact same hardware but having slight diffences in functionality, is not compatible with the unit the user wants to upload it to.
Unless Rigol is hand-soldering every device specifically for the customers, eaach one in turn being different, it is really hard to believe that you need to have that begging-for-firmware procedure in place. If the firmware needs to be specific for a few model revisions and/or serial number ranges, but the units are unable to figure it out on their own, then simply put that information out there together with those files. You know, like "here is firmware version A. This version is only for the series B units, hardware revision C and serial number range XX to YY. Do not apply to other units". Again, you had no problem providing a beta firmware to people without any such restrictions/information attached, which strongly hints at this not really being an issue. Don't treat your customers as stupid folks who can't read, have some confidence in them, please.
Greetings,
Chris
ETA: And as has been suggested already, if the beta firmware does not allow "downgrading" to the previous non-beta version, then simply provide the previous version with a changed version number (or whatever) so that the beta recognizes it as an update and will "update". You want people to help you figure out the issue, the least you can do is to help them revert back after they tried the beta, found issues and reported them.