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TwinKick: Dual Kickstart Boot via Floppy for Amiga 1000

by intric8 Mon Oct 09, 2017 5:02 pm

Check a video demonstration of the software discussed in the post below.

The Amiga 1000, aka “The Amiga”, has often had a schizophrenic reputation with Amiga Lovers. On the one hand, it’s the best looking and most iconic Amiga ever made. On the other hand, it was shipped at a mechanical “disadvantage” as it never shipped with a Kickstarter ROM chip. All of the other Amiga models did. Amiga 1000 users were expected to manually load the firmware on every boot via a floppy disk.

To the uninitiated, a Kickstarter ROM is firmware - basic instructions the machine uses to initialize it various components while booting up. After it has done so, it will then ask for (or seek) its corresponding Worbench file, which is the graphical OS file manager.

If an Amiga user - except those on the 1000 - ever wanted to upgrade their firmware, they had to crack open their machine’s case, find the ROM chip and replace it with a newer version. It’s generally one of the most painless upgrades an Amiga user could perform to their hardware as long as they were careful not to bend the legs of the chip. But it did require “surgery” and some time. And as cool as some of the new features newer ROMs provided, they sometimes broke compatibility with some of the software of the past. So, it wasn't always without some pain points.

The most across-the-board compatible Kickstart ROM ever created for the Amiga was KS 1.3.

99.9% of all Amiga software was written not just to work on 1.3, but was aimed directly at it. The reason being is that 1.3 shipped on the vast majority of Amigas ever made, particularly the popular Amiga 500. But over time there were perceived needs and business goals to move towards KS 2.04, and eventually KS 3.1, especially when it came to using and managing IDE hard drives. Kickstart 3.1 could also autodetect some of the third-party memory expansions, and was needed if you ever wanted to install OS3.9 (which better supported hard drives larger than 4GB). There are a few other little things, like the ability to easily create folders (i.e. not having to always keep an “Empty” folder nearby). At the end of the day, most of the improvements were fairly minor. But in later years some of the public domain software on Aminet was coded specifically for 3.1. And, to its credit, 3.1 is mostly backwards compatible.

What all Amiga users other than those on the 1000 eventually ask themselves is, “Should I get a Kickstart switcher?” This is an inexpensive little device that can be installed inside the machine that allows two separate Kickstart ROMS to be installed. Users could then invoke whichever they wanted or needed at any given moment. And suddenly, they can have the best of both worlds: 100% software compatibility, as well as slightly easier hard drive management, etc.

Meanwhile, the 1000 - which loads its Kickstart via floppy disk - sat left behind and was mostly forgotten.

The 1000 launched to the public on KS 1.1 before Commodore quickly released “Enhancer Software” upgrade disks for 1.2 and, finally, 1.3. Some hardware solutions became available to install Kickstart ROMs, but they typically required cutting traces on the 1000's motherboard and soldering. In other words, pretty permanent upgrades that require a bit of skill and bravery to perform.

Back in 2002, long after the death of Commodore, a programmer named Andre Pfeiffer released code to Aminet which I believe revealed the Amiga 1000’s KS loading sequence to be a potential advantage. It is called TwinKick.

TwinKick is a tool that “generates a [K]ickstart disk for the A1000-Amiga with OS1.3 and OS3.1 on 1 disk.” Both Kickstart ROMs on a single floppy!

It took me a little while to figure out how to use the final compiled disk, but with user mattsoft’s help I was able to get it to work.

How to use TwinKick:

Booting KS 1.3

Insert your TwinKick disk and turn on the power. In a few moments your screen will start to flicker between white and gray as the machine begins its initial checks. Immediately eject the disk once the screen first starts to flicker. Don't eject it when the disk is being actively read! If you're unsure, you can watch when I eject the disk in this 6-minute video.

At this stage, the Amiga 1000 will present the “Insert Workbench 1.3” screen with the iconic crude hand holding a blue disk. You'll know everything is working correctly as you'll see some new tiny text stating that this is TwinKick
Note the small text of "TwinKick" below the disk. If you see this, you're in business.

Booting KS 3.1

This whole process was magical for me the first time I did it. If you insert TwinKick and simply do nothing at all, after a few moments your screen will start to “freak out” then switch to a gorgeously rendered black and white photo of an Amiga 1000.
Behold the TwinKick 3.1 loading eye-candy screen (with instructions in the upper-left corner).

Wait a few more moments and voila! Your Amiga 1000 will display the legendary 3.1 magenta screen with the looped animation of the disk inserting into a beige floppy drive. If you’ve got your Workbench 3.1 disk handy, you can go for it!
KS 3.1 loaded onto the Amiga 1000 using the same floppy disk I used to load KS 1.3. No hardware mods were necessary to perform this magic.

So, with a single floppy disk, Amiga 1000 owners have this incredibly bad assed ability to run either Kickstart ROM without one single hardware modification made to their machines. That sounds like an advantage to me. Before the 3.1 screens load, you'll be presented with a gorgeous rendering (or scanned photo) of an Amiga 1000 with some instructions in the upper left-hand corner. They're for folks who are in 3.1 but want to soft-reset into 1.3 by holding the right mouse button. I only got this to work once. For 1.3, I simply eject the disk at the right time as that works every single time.

Also, you need to have at least 2 MB of RAM on your machine for this to work:
The kickstart requires an A1000 with 2MB or more FastMem from Adr.
$ 200000 (works with AutoConfig and NonAutoConfig extensions)
(However, only one external memory extension is supported!)
My expansion RAM automatically addressed at this location by default.

It might be a tiny bit slow, but hell - all of these machines are compared to devices created today. Grow a little patience, right? It’s all part of the retro experience. As long as it works, that’s really all that matters to me most of the time.

I also recorded a short video demonstrating TwinKick booting into both 1.3 and 3.1 off the same disk. Check it out over on YouTube.
Huge props to mattsoft for keying me into this very cool software for the Amiga 1000. Thanks, Matt!
Amiga 1000 Inception

If you liked this post you might also be interested in another article I wrote about some software called KickWork for the Amiga 1000, which will load both Kickstart and Workbench from a single disk. Very cool stuff!
Posts: 57
Joined: Sun Jun 25, 2017 7:22 am

Re: TwinKick: Dual Kickstart Boot via Floppy for Amiga 1000

by mattsoft Mon Oct 09, 2017 5:42 pm

Nice write-up! It's always weird (and cool) seeing 3.1 boot on a 1000. :)

Here's how you make a TwinKick boot disk for your Amiga 1000:

1. Head over to Aminet and download TwinKick:

2. You'll need to expand the LHA archive and get it onto your Amiga or into UAE. I have an ACA500plus connected to a 500, so I copied TwinKick to a CF card.

3. You'll also need the KickStart ROMs for both 1.3 and 3.1.

However, if you make TwinKick from an Amiga with 1.3, you just need the 3.1 ROM.

Conversely, if you make TwinKick from an Amiga with 3.1, you just need the 1.3 ROM.

This comes in very handy later on, so I recommend you make TwinKick from a 1.3 or 3.1 machine, and not a 2.x machine.

As for ROMs, you can either use the Cloanto ROMs:
Kickstart v1.3 rev 34.5 (1987)(Commodore)(A500-A1000-A2000-CDTV).rom
Kickstart v3.1 rev 40.63 (1993)(Commodore)(A500-A600-A2000).rom

Or you can use the excellent GrabKick tool ( to dump your Amiga's ROMs to disk.

Either way, you should legally own both versions of Kickstart.

You'll need to name your 1.3 ROM "KICK13.ROM" and your 3.1 ROM "KICK31.ROM". Mind the case, it matters!

4. From your Amiga, format a disk.

Copy the TwinKick "TKG.EXE" to the blank disk.

Copy the version of the ROM file your Amiga DOES NOT have to the blank disk. For example, if your Amiga is 1.3, copy KICK31.ROM to the blank disk, or vice-versa.

If you are making this on a 2.x ROM Amiga, the blank floppy will not have enough room for KICK13.ROM, KICK31.COM, and TKG.EXE. You will need to run TKG.EXE from a different volume.

5. Make sure the disk with TKG.EXE and the KS ROM file is in df0:.

From a shell, run TKG.EXE and follow the prompts.

It will read your KS from ROM and from disk and then ask you to insert a floppy and click LEFT mouse button for a PAL disk, or RIGHT mouse button for NTSC. You can put another foppy in or just leave your floppy in the drive (what I did).

Click the appropriate mouse button.

1 minute later you have a TwinKick disk. It's that easy!
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