MacOS 9.2.x - Upgrading pre-G3 (Old World) Macintosh and clones.
OW Macs are not supposed to upgrade higher than MacOS 9.1. Some smart guys of the Mac community have found out how to install 9.2.1 and 9.2.2 on OW Macs.
Everyone who tried to run the installer on an OW got a message saying something like ÒcanÕt run on this computerÓ. There are two techniques to avoid this bottleneck. The first technique will let you run the genuine installer, the one you download from the official Apple servers. The second technique will drive you to modify the genuine installer before running it. Both techniques have been tested in various environments, achieving almost the same visible result.
A) Running the genuine (official) update installer from Apple (any language)
Although Nubus-based computer might be eligible to 9.2.x update, the following instructions apply to PCI computers.
A.1) Deceiving the genuine installer
ItÕs possible to run the genuine update installer on any computer. The only thing to do is to deceive the installer so that it believes the computer itÕs running on is not an OW. The trick is to change the internal model code, the Òmach IDÓ. You can complete this step through two different ways.
A.1.a) The simplest one is to use an application dedicated to this limited task, such as ÒMachID WannabeÓ. You can find it on http://homepage.mac.com/cywong/FileSharing.html. It will temporarily (until next restart) change the ID of your computer for the code of a G3, which is recognized as a legal computer by the update installer.
A.1.b) The hardest way goes through a program that gives read/write access to a set of internal variables. ÒGestLabÒ is such a program. You can find it at http://www.geocities.com/jp_curcio/.The variable we are looking for is named ÒMachÓ. This is the model code. Then you can make by hand what ÒMachID WannabeÓ performed automatically, i.e. change the Mach ID to 510 (decimal).
Once you have changed the model code (no matter which method you used) you can run the update installer. DonÕt restart ! You can run updater 9.2.2 after updater 9.2.1.

Now you have installed a true MacOS 9.2.2. But the system youÕve installed is not yet compatible with you computer. DonÕt try to reboot on this system, it wonÕt work. All the files that where installed (extensions, finder, etc.) but the System suitcase are OK. So you will need to patch that file.
A.2) Patching the system suitcase (language dependant)
Patching a file can be done in two different ways.
A.2.a) The simplest way is to run a special patch application, that has been designed to make the very precise modifications of resources needed by your system. You need a patch program designed for your localization of Mac OS. You can find such a program for US versions at http://homepage.mac.com/cywong/FileSharing.html.
A.2.b) The hardest way works fine with any localized version. It requires that you get a file containing the modified resources set and a resources editor program that lets you transplant the modified resources into you own localized system suitcase. You can find the resources at http://homepage.mac.com/cywong/FileSharing.html. The ResEdit resource editor (http://developer.apple.com/tools/ResEdit213.hqx) will do it fine.
Follow the step below :
i) backup of your system suitcase (file)
ii) launch your resources editor
iii) open the System file
iv) open the resources set
v) for each kind of resources that appear in the resources set
    copy the kind
paste it in the system file (choose override)
vi) save the ÒpatchedÓ system file
vii) quit the resources editor

Now, you have patched your 9.2.2 system. You can select it as your boot system.

B) Patching the installer (language dependant)
An alternate technique is to patch the installer itself so that :
i) the installer will run on an eligible but not legal computer
ii) the installer will install the patched resources

A patch application has to be designed for each localized version and for each update (9.2.1 AND 9.2.2). Look at ftp://ftp.gps.caltech.edu/pub/kby/ if there is a patch application for your genuine updater disk image. Remember that these patches must be applied to disk images that were never mounted (set the appropriate preferences in your browser and unstuffer utility).
i) run the patch application
ii) open the disk image file
iii) save the patched disk image file
iv) mount the patched disk image
v) run the installer

Your updated system is ready for use.

If you donÕt find a patch application for your localized version of the 9.2.1 updater you will have to run the genuine installer as described in part A.1 (donÕt perform A.2).

C) Known problems and solutions
Dark screen
Some users report that the first try to reboot on the patched system results in a black screen. Forcing hard restart does not solve the problem. All you need is to restart you computer while pressing cmd-alt-P-R keys simultaneously. This will zap the PRAM and solve you problem. Be careful, some system settings may have been reset to their default value.

Quit Finder
This problem was mainly experienced by user who have plugged-in a FireWire card. To know if you computer is sensitive to this problem, you can open a pdf document with Acrobat Reader 5.0.5 and try to switch (cmd-tab) many times from this app to the finder, close the document, reopen it (many times). Do it again. If all goes fine, then forget it. If the finder quits or if you experience hide/display problems, than you need to edit the ÒFinderÓ file.
i) backup your finder file
ii) open the Finder file with your resources editor
iii) open the SIZE set (it contains one element)
iv) open the element
v) increase the size (this is the equivalent of the ÒmemoryÓ info [cmd-I] of a regular application)
vi) access the information panel (cmd-I)
vii) set ÒpurgeableÓ, ÒprotectedÓ, and ÒpreloadÓ options to true (active, yes, select).
viii) save the Finder file
ix) quit the editor.

Micellaneous
The whole story
If you want to know what you are doing and who are the smart guys who made this possible, you can read the whole story from two macfixit forums :
http://www.macfixitforums.com/php/showthreaded.php?Cat=&Board=OS92&Number=299351&page=0&view=collapsed&sb=5&o=7 

http://www.macfixitforums.com/php/showflat.php?Cat=&Board=OS92&Number=336400&page=0&view=collapsed&sb=5&o=7&vc=1
My system
I have tested this informational material on my own system before suggesting other people to use it [therefore, my warning about NuBus based machines]. My machine is quite far from a conventional Apple Macintosh computer :
Apus 3000, a PM6400 clone by Umax, built on a Tanzania Ð4400- motherboard designÉ
Sonnet L2/G3 overclocked upgrade card
iRez Ultimate enhanced graphic PCI card
SMC (cheap) 10/100 Base-T Ethernet PCI card (PC store)
unbranded USB/FireWire PCI card
30  G-bytes downgraded Western Digital UDMA internal disk (PC store)
32x SCSI-internal TEAC CD-ROM reader (PC store)