Kickstart 3.9

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Kickstart ROM 3.9

Kickstart 3.9 Boot Screen
Kickstart Version 3.9
Kickstart revisions 45.x
Max Compatible OS AmigaOS 3.9
Available for Amiga models A1200, A4000, A4000T
Date Released 2006
ROM size 512KB


Kickstart 3.9 Information

Kickstart 3.9?

There wasn't an official Kickstart 3.9 ROM released by Commodore, or any other Amiga company. Kickstart 3.9 is instead is a custom "scene/homebrew" ROM created by the Amiga community for use with AmigaOS3.9.

What is the Kickstart 3.9 ROM?

Although AmigaOS 3.9 boots fine using a Kickstart 3.1 ROM, before AmigaOS 3.9 actually loads it normally first needs to patch the system by running setpatch to add the additional AmigaOS ROM Updates required for 3.9, and then once they are loaded/patched the system reboots and then loads AmigaOS 3.9.

Logically, had Commodore still existed they probably would have released an updated kickstart ROM that contained the updates this Patch adds, instead of needed to patch the system in memory every time it boots. This is where this custom Kickstart 3.9 ROM comes in. By combining the files from the original Kickstart 3.1 ROM with those included in the AmigaOS 3.9's ROM Updates and making a new updated ROM it removes the Amiga's need to first need to run the setpatch to add the newer files into the system.

How is this achieved?

The custom 3.9 ROM is built by combining the files from the original Kickstart 3.1 ROM version, with the files from the AmigaOS 3.9 ROM update. And a new ROM is then built which contains both. Therefore allowing the Amiga to boot into AmigaOS 3.9 without first needed to patch the system and perform a soft reboot.

And while creating this custom ROM image you can take the opportunity to customised the files it contains for your own needs. For example you could remove the original scsi.device from the ROM image if you don't use the Amiga's original on-board IDE interface, and instead add a different device driver needed for the HD hardware you actually use, such as 1230scsi.device.

How to make a Kickstart 3.9 ROM set

You will need:

  • A Willem EPROM programmer and Windows PC to control it. - see official Willem site
  • 2 16-bit EPROMs.
  • Doobrey's RomSplit and Remus utilities - see Downloads

The process to make a Kickstart 3.9 ROM set is as follows:

  • Read the contents of your 3.1 ROM chip into an image file.
  • Use Doobrey's RomSplit utility to split the resulting image file into it's component parts (the files contained within it).
  • Use Doobrey's RomSplit utility to split the AmigaOS 3.9 AmigaOS Rom Update files into it's component parts (files).
  • Combine the 3.1 ROM's files with the ones in the newer AmigaOS 3.9 ROM Update. Replacing any older versions from the 3.1 ROM files with the newer ones contained in the 3.9 Update.
  • Remove any files that you won't need, and add any additional ones that you require. As mentioned above, you could remove scsi.device from the rom if you don't use the on-board IDE interface, and replace it with a different file such as 1230scsi.device.
Note: When doing this make sure you keep an eye on the complete ROM size. While your EPROMs might be larger, the Amiga expects to find a 512KB ROM image, so your final total ROM size must remain that size.
  • Build these files back into a ROM image, by combined the files using the Remus utility.
  • Next test the image by using BlizKick (or another method of softkicking a ROM image on a real Amiga).
  • Next copy the ROM image to a Windows based PC and load the image into WinHex
  • Dissect the file Wordwise, and create 2x256kb files (so it is split to fit onto the two physical Kickstart EPROMs. Which creates the two files U6A_tmp.bin and U6B_tmp.bin
  • Concatenate U6A_temp.bin to itself to create U6A.bin, with a filesize of 512K and do the same for U6B.
  • Load each image into the Willen programming software, perform a Byte Swap operation on the buffer, and then write each image to the EPROM chips.
  • Install them into your Amiga as you would a normal Amiga ROM and you are finished!


You will need the following software from DoobreyNet to split ROMs into component parts, and to combine files to make the new ROM image.

RomSplit rips rom images apart into it`s component parts (plus 'AmigaOS Rom Update' files and Piru`s Exec44).
Currently only v40.68 (A1200,A4000D,A3000,AmigaForever),v40.70 (A4000D,A4000T,A3000), v40.63 (A500/600/2000) and V39.106 (A1200,A4000) are supported.
Remus can take any component parts and build them back into a rom image.
It can also take Blizkick modules and patches, and can actually it can take any file in the standard amiga hunk format, as long as there`s at least 1 valid resident structure and no BSS hunks.


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