IBM stopped supporting it, so I'm putting it here. You should use it ONLY if you have machine, and personally I don't see any usage of this BIOS update if not for updating the machine :). This copy is put on site for backup purposes, as IBM ceased support for their old PowerPC computers.
1. License
2. If you agree, use archive password
3. Instructions

1. License
RS/6000 License Agreement for Machine Code
Regardless of how you acquire (electronically, preloaded, on media or otherwise) BIOS, Utilities, Diagnostics, Device Drivers or Microcode (called "Machine Code"), you accept the terms of this Agreement by your initial use of a Machine or Machine Code. The term "Machine" means an IBM machine, its features, conversions, upgrades, elements or accessories, or any combination of them. Acceptance of these license terms authorizes you to use Machine Code with the specific product for which it is provided.
International Business Machines Corporation or one of its subsidiaries ("IBM"), or an IBM supplier, owns copyrights in Machine Code.
IBM grants you a nonexclusive license to use Machine Code only in conjunction with a Machine. As the rightful possessor of a Machine, you may make a reasonable number of copies of Machine Code as necessary for backup, configuration, and restoration of the Machine. You may authorize a third-party contractor or service provider to exercise these rights on your behalf and for your benefit. You must reproduce the copyright notice and any other legend of ownership on each copy of Machine Code you make.
You may transfer possession of Machine Code and its media to another party only with the transfer of the Machine on which the Machine Code is used. If you do so, you must give the other party a copy of these terms and provide all user documentation to that party. When you do so, you must destroy all your copies of Machine Code.
Your license for Machine Code terminates when you no longer rightfully possess the Machine.
No other rights under this license are granted.
You may not, for example, do any of the following:
    Otherwise copy, display, transfer, adapt, modify, or distribute in any form, Machine Code, except as IBM may authorize in a Machine's user documentation;
    Reverse assemble, reverse compile, or otherwise translate the Machine Code, unless expressly permitted by applicable law without the possibility of contractual waiver;
    Sublicense or assign the license for the Machine Code; or
    Lease the Machine Code or any copy of it. 

The terms of IBM's Machine Warranty, which is incorporated into this Agreement by reference, apply to Machine Code. Please refer to that Statement for any questions or claims regarding performance or liability for Machine Code.

Form No.: Z125-5468-01 9/99 


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2. Password
You should record this eleven character "case sensitive" password:
Password: **RS/6000**
You must enter this password to unzip any microcode file. You now have all you need to download RS/6000 microcode. 


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3. Details
7240/6042 Microcode

7249/6042 microcode description
New level description
This release of microcode for the 7249/6042 Series of ThinkPad Power Series is version 1.01.

Year 2000 Support
For model 851 of machine types 7249 and 6042, system microcode must be updated to be Year 2000 ready*. Note that this statement does not apply to the product 7249 Model 860 whose system microcode is Year 2000 ready* as shipped.

You will want to upgrade your microcode to version 1.01 to ensure that your system is Year 2000 ready*. This update provides other functional enhancements. See the next section.

* Please consult the IBM Year 2000 web page at http://www.ibm.com/IBM/year2000 for IBM's definition of "Year 2000 ready" and the latest information of the status of IBM products and the Year 2000.
Enhanced Function
It contains all of the features of the previous release, 1.0, plus the following enhancements and fixes:

    ROM code updates RTC Date registers improperly.
    PCIC registers are not initialized on warm boot.
    Flash ROM write-protect is not enabled when OS boot.
    NT Shutdown & restart causes ROM hang.
    ROM code updates RTC Date registers intermittently.
    Windows NT ARC reports an internal error.
    MPC105 REV2.4 Errata workaround should be applied.233Mhz Processor support.

You will want to update your microcode if you would like to add these enhancements to your system. Users are encouraged to upgrade to this version.
Previous level description
FW VERSION : 1.00 ROM BUILD DATE : 07/03/95
How to determine your microcode version

To check your microcode version:

    Enter Easy Setup by pressing the F1 key at the power on time.
    Select Test icon.
    Enter Super Test by pressing the Ctrl + A keys.
    Enter Maintenace Utility by pressing the Ctrl + V keys.
    Select System Info.
    System ROM version number shows the current firmware level. ** If System ROM version number is 1.01, the machine is already applied this Firmware change.Turn on or shutdown and restart the computer. 