Well, it's been a while...

So, I have an ISY994 with a 300 series Z-Wave board. It's on 5.0.16C. It's connected to a serial PLM for Insteon devices (those are the pieces I currently care about).

I've moved my Z-Wave devices to another controller setup and don't care about the z-wave within the ISY, at this point (old, range issues, etc).

If I remove the board and flash the 5.3.4 firmware, will it all work fine? I'm currently flashing the oadr firmware. I also never ended up using any of the Open ADR stuff, so do I just flash the "insteon" labeled firmware and then restore my backup, or will it complain? I have the original zigbee board, somewhere, as well. But I never kept anything which used that protocol (hence the current Z-Wave board).

Are there any non-Z-Wave features/bug fixes which would make all of this idea worth it., or no?

My end goal is to use the controller for as long as I can, without hassles, on the least problematic firmware. At least, until such time that I bother to make it all work under some other controller, or the devices all give up (some have started, but I only have so many backups and only so much patience for replacing parts, etc).

Yes, you can remove the zwave board and then update to 5.3.4. There shouldn't be any issues updating. Each subsequent release contains bug fixes and enhancements

Be sure to read the update release notes

5.3.4 (ISY994) - Last release for ISY994 - Current Release Announcements - Universal Devices Forum

Cool, thanks.

I checked over various release notes, I was just mostly seeing z-wave details (other than a maybe an item or two like the one where different unit precisions messed with triggering programs).

I'll just do the normal backup step and give it a go, then. Worst case, I'm forced to transition everything, which isn't the end of the world, just not what I'd like to plan to address right now.

With the isy994i, you can still download and install older versions, "downgrading" if needed. Just make sure you have backups before installing new versions.

With newer devices like the eisy, older versions aren't necessarily available. That's why I personally back up the entire contents of the SSD (unix and all) before any major updates.