Install Mac OS 7.5.3

This is the third and final part of several mac related tutorials. The first part can be found here (Install Macintosh System 6) and here (Create Large (4GB > x > 20 MB) Mac CHDs) is the second part.

After completting this tutorial, you should be able to upgrade to Mac OS 7.5.5 and 7.6 but notice that the Mac IIcx was not designed to sport any OS above 7.5.5.


You will need some file prior to get into this tutorial

Working installation of Mess

Minimum Recommended Version is Revision 9050 (Some revisions after the 0139u2 milestone)

Working installation of System 6

Go to this page for more information

Installation disks of System 7.5.3

You will need installation disks which are available here : iiNet old Software list. Look for:

  • System_7.5.3_01of19.smi.bin
  • System_7.5.3_02of19.part.bin
  • System_7.5.3_03of19.part.bin
  • System_7.5.3_04of19.part.bin
  • System_7.5.3_05of19.part.bin
  • System_7.5.3_06of19.part.bin
  • System_7.5.3_07of19.part.bin
  • System_7.5.3_08of19.part.bin
  • System_7.5.3_09of19.part.bin
  • System_7.5.3_10of19.part.bin
  • System_7.5.3_11of19.part.bin
  • System_7.5.3_12of19.part.bin
  • System_7.5.3_13of19.part.bin
  • System_7.5.3_14of19.part.bin
  • System_7.5.3_15of19.part.bin
  • System_7.5.3_16of19.part.bin
  • System_7.5.3_17of19.part.bin
  • System_7.5.3_18of19.part.bin
  • System_7.5.3_19of19.part.bin

Once uncompressed, the first get a “.smi” extension and the others a “.part” extension. Put the whole lot into a folder to make things easier.

I recommend to lock these files since nothing should be allowed to alter them.

A large HD

To be honest Mac OS 7 don't need enormous drives, but past the 20 or 80 MB limit the Apple formating tool starts to act strangely. So I recommend downloading these pre-made images or following these instructions to get a fully functionable Mac HD.

Both a 640 MB and a 4 GB disks are used in this tutorial. The 640MB is made into an “installation disk” and the 4GB is used as our Mac IIcx Internal HD.

If you are planning on installing an older version of Mac OS, be aware that there is volume limitations. For instance, after System 6 and before System 7.5 the limitation is 2GB. Starting with 7.5 the limitation is raised to 4GB.

Like when creating large drives, at one point in this tutorial, you will have to copy files from your real computer to an image. To this end I use BasiliskII since it got a handy “sharing” function. Yet, you will need a working installation of BasiliskII with a functional OS in it.

HFSExplorer seems to be an alternative for getting things done, yet I can't test this method right now. Feel free to expand this part if you can.


Part One : Create an Installation Disk

  • Convert the 640MB chd into suitable Basilisk drive image :

chdman extracthd -i newmachd640m.chd -o newmachd640m.dmg

  • In Basilisk now, mount the newmachd640m.dmg and use the native sharing function to copy your folder containing the installation files onto both your Basilisk boot disk and your new newmachd640m.dmg.
  • Run “System 7.5.3 01of19.smi” from your boot disk, “Agree” and it will mount a virtual drive onto the desktop
  • In this drive named “Sys7.5 V7.5.3 CD Inst”, Run “Installer”
  • “Continue”
  • “Switch Disk” until you get your new drive
  • In the Popup menu “Easy Install”, switch to “Custom Install”
  • Under “System Software”, check the “Minimal System for any Macintosh”
  • Push the “Install” button
  • “Quit”

At this point you may be interested in putting other tools onto your “Installation disk” like Stuffit Expander, Mac OS 7.5.5 upgrade or some disk tools. Yet, nothing more is needed for completting this HowTo.

  • Turn off your virtual mac and quit basilisk
  • Convert back the Basilisk image to use it for MESS :

chdman createhd -i newmachd640m.dmg -o newmachd640m.chd

You may rename it as macos753inst.chd

You should have now everything needed to perform successfully an installation of MacOS 7.5.3 under MESS.

Part Two : Install Mac OS 7.5.3 Under MESS

  • Boot MESS with mounted hard drive (with path changed accordingly). In the following, we use maciicx as driver as others may not work properly. Command line:

mess maciicx -hard1 macos753inst.chd -hard2 newmachd4000m.chd -ramsize 128M

NB : about the ramsize parameter, 128M may be overkill, but the default value is to low (although may be not during the installation). Fell free to experiment lower values if you need to.

  • After booting, open the new “Installation Disk”, open the folder in which you stored the install files and run “System 7.5.3 01of19.smi”
  • In the drive named “Sys7.5 V7.5.3 CD Inst”, Run “Installer”
  • “Continue”
  • “Switch Disk” until you get your new 4GB drive

Here you may chose yourself if you prefer to go custom or stay on easy install. My advice here is, if you want to be able to use this disk with other upcoming drivers, you should go custom, and check all options (that will include software not needed for the IIcx but useful for other macs).

  • Push the “Install” button

If you have enabled a “Fast Forward” key, go for it.

  • “Quit”

You're Done, Just halt the mac using Menu “Special > Shut Down”. You should now be able to boot your freshly installed Mac using :

mess maciicx -hard1 newmachd4000m.chd -ramsize 128M

You have now a valid 7.5.3 CHD suitable for MESS, and that can be exported for use in Basilisk (Here for more about that).

Here’s a set of already formatted and partitioned blank Mac hard disk images (.CHD). Big thanks goes to Grégoire Duval and Arbee.