Tiger OS 10.4 is the max OS for PowerBook G4s below 867MHz.
Tiger install DVDs are in short supply. Tiger is no longer available at the Apple Store but may be available by calling Apple Phone Sales @ 1-800-MY-APPLE (1-800-692-7753). For other sources, do a Google search for MA453Z/A (10.4.6), MA190Z/A (10.4.3) and M9639Z/A (10.4). Also look on eBay. Be sure & buy a retail version
and not a model specific version (gray) (See http://discussions.apple.com/thread.jspa?threadID=1976068 Can I use another Mac's system restore disc on my Mac?.
Also check these web stores: http://www.lacomputercompany.com/cgi-bin/rpcart/index.cgi?command=dispitem&type= sku&sku=19521
http://www.allmac.com/shop/index.php?cPath=5_10003
Possible Alternative if you are currently using Panther 10.3 – Do a Google search for Tiger 10.4 Upgrade DVD . It will upgrade your 10.3 to 10.4, but it doesn’t contain the full retail Tiger installer. Should be cheaper than the retail Tiger install DVD.
After you install the base 10.4.x, update to the final Tiger version 10.4.11. Here's the link for the 10.4.11 combo update http://support.apple.com/kb/TA24901?viewlocale=en_US
Look at this link Mac OS X v10.4 Tiger Installing Software Support Page
http://www.apple.com/support/tiger/install/
You can also download the Tiger Installation and Setup Guide
http://manuals.info.apple.com/en/Tiger_Install_Setup_Guide.pdf
When you upgrade the OS, do it via Archive & Install. See About the Archive and Install feature http://support.apple.com/kb/HT1710
Be sure to select Preserve Users & Settings. Also, repair permissions before and after the install.
Leopard OS 10.5 is the max OS for PowerBook G4s above 867MHz.
Mac OS X 10.5 Leopard installation system requirements
http://support.apple.com/kb/TA24950
Leopard is no longer available at the Apple Store but may be available by calling Apple Phone Sales @ 1-800-MY-APPLE (1-800-692-7753).
If you can't obtain a retail install DVD from Apple, look on eBay or Google the installer part numbers to possibly find at an on-line store. Here's what to look for:
MB427Z/A Leopard 10.5.1 install DVD
MB576Z/A Leopard 10.5.4 install DVD
MB021Z/A Leopard 10.5.6 install DVD (single user)
MB022Z/A Leopard 10.5.6 install DVD (5-user family pack)
Installing Mac OS X 10.5 Leopard
http://support.apple.com/kb/HT1544
Mac OS X 10.5 Leopard Installation and Setup Guide
http://manuals.info.apple.com/en/leopard_install-setup.pdf
After you install the base 10.5, download & install the 10.5.8 combo update at http://support.apple.com/downloads/Mac_OS_X_10_5_8_Combo_Update
The DVD should look like this
Caution - Leopard does not support classic mode. So, if you currently open OS 9 apps in classic mode, you won't be able to do this if you upgrade to Leopard.
Cheers, Tom 😉
