So, which kickstart do you want? what’s right for you and your machine? I can’t tell you this, but I can lay out some reasons that you might make specific choices.
You want it “classic”?
If you have an early, unmodified, “chickenlips” A500 with space invader keyboard and a red power light, you you might want to go for the original A500 kickstart 1.2 ROM, same will go for all the classic machines.
Do you want an A600 with the last Commodore ECS setup? Kickstart v2.05/r37.350 with Workbench v2.1 is for you then, or you can run v3.1/r40.63 as it was the official/production/RTM update for the A600 (and other 68000 based Amigas) and you’re still “classic”. Same goes for the A1200, although it originally came with v3.0, the definitive last version was v3.1/40.68
If you have an A3000, then perhaps the best classic kickstart is v1.4/r36.16, this was the only public beta burnt to mask ROMs, so you might want to consider it a production/RTM release, the great thing about it is that it allows you to select between the original v1.3 ROM and later ROMs via the Superkick feature – you’ll unlikely actually be running on the v1.4 ROM itself (although you can), originally designed to switch between v1.3 and v2.x you can create boot files to boot v3.1 (and beyond), so perhaps this is the ideal machine.
The A4000 has final Commodore releases for v3.1, but depending on your hardware you may want to select r40.68 or r40.70, and note the final A4000T release didn’t have workbench.library in ROM but was loaded from a WBFind stub instead.
The CD32 is simple, the main release was v3.1/r40.60 and there’s not any other classic choice for a “normal” CD32, which of course isn’t the full picture, very early machines were released with r40.16, there were a few production machines with r40.56 mask ROMs, and there’s special ROM for CD32’s with the official developer boards attached (a hard driver was pretty much the only addition).
The CDTV is a tricky one, it originally came with v1.3 but also supported v2.04/r37.175, however, the main boot ROM has to be compatible with the extended rom, so if you upgrade to v2, is it still classic? How official a v2.0 CDTV would be is debatable, at least one of the extended ROMs floating around is actually a hack of the A570 ROM.
You want it compatible?
Well, what is compatible?
Firstly, you need to support your hardware, if it’s an unmodified classic machine, that’s relatively easy, for example, if you have an A600 and a hard drive, you don’t want anything less than v2.05/r37.300 and your hard drive won’t boot using a standard ROM, you probably want to support your chipset, i.e. ECS wants KS2+ and AGA wants KS3
If you need to run an older kickstart to support a game or app, you can run a softload kickstart from floppy like ReloKIck, although this does eat up a chunk of memory, so you might need some expansion RAM.
Perhaps the best compatibility is to have the last official release v3.1 and use WHDLoad to run classic games and apps that need older versions (e.g. v1.3), however, you’ll need a hard drive and RAM upgrades to run WHDLoad.
If you have an accelerator or add in card then you’ll probably need to add support library(ies), this is typically done from the hard drive, but you can create your own ROM or modify an existing one to support it, for example, the TerribleFire cards have an onboard IDE interface which needs an ehide device library to be able to boot.
You want an update past the original?
What is the latest and why do you want it? if you just want to run a few classic games, then you may not benefit from upgrading at all.
There’s three routes to updating from the classic Commodore ROMs, Haage & Partner, Cloanto and Hyperion, they all have different advantages and disadvantages, pretty much all of them will require you to run a hard drive and extra memory, in some cases significantly more memory, all will break compatibility with badly written, classic games, but again, you can usually get round this by using WHDLoad.
Note, you can either burn (or buy) a dedicated physical ROM or you can load the newer modules into RAM, RAM is often faster (and with things like Blitzkick significantly faster) but if you don’t have much RAM, that’s not going to end well, especially as hard drive buffers can suck up a lot (although you can tune it). If you’re very limited on memory and still want an update >v3.1 then consider burning a 1Mb ROM with all the extras in.
Haage & Partner 3.5/3.9
No official ROM was created, instead, you use v3.1 and add “loaded ROM modules”, officially these were based on the original Commodore source code, there were two releases, v3.5 and v3.9, you can of course mic you own ROM if you want, adding in the modules you want, I don’t think there’s any “new” copies for sale these days, but you can still find second hand versions for sale (obviously considering the licencing issues in your jurisdiction).
Cloanto 3.X
These were released as 3.X (capital X), and included lots of updated modules, to support larger hard drives, 68060 accelerators and many other bug fixes, these are still available to buy, this can be a nice update if you want to support some later hardware, but don’t need the very latest.
Hyperion 3.1.4/3.2
These are the latest and still actively developed kickstarts (and OS), they have support for large hard drives and accelerators, don’t be confused by the version number, v3.2.2 is (at time of writing) the latest version and significantly more recent than the commodore v3.2 and H&P v3.9
You want to make your own?
Capitoline is all about the ability to make and edit your own ROMs, and there’s several reasons why you might want to do this.
Adding functionality
Maybe it’s as simple as adding support for your hardware, this can be really simple, or really complex depending on what ROM you’re basing it on and what hardware you want to support.
Saving memory
If you’re short of memory and you want to put some libraries in the ROM, this is a great way – assuming your Amiga can cope with larger ROMs, this could be ideal for adding back libraries that have been removed for space reasons, for example, building a 1Mb Hyperion ROM will allow you to put back workbench and icon libraries and save a chunk of memory – note, while this saves memory and boot time, accessing physical boot ROM memory locations may be slower than accessing modules loaded into memory if you have an accelerator or “true” fast memory.
S & G
You might just want to make your own ROMs because you fancy doing it, maybe you want to change the copyright notice to “Mikey is great”, maybe the hand logo on kickstart v1.3 annoyed you because it faces the wrong way and you want to edit it, maybe you want the challenge, to understand a bit more, just to see if you can, or for shits and giggles.