HW3Patch 1.00 by Kevin Kofler
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QUESTIONS AND ANSWERS:
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Q: What is the HW3Patch?
A: It is a program which modifies TI's Advanced Mathematics Software operating
   system in a way which allows memory-resident programs (TSRs), dynamically-
   linked libraries (DLLs), nested function trampolines and similar constructs
   to run.

Q: What hardware and software versions does HW3Patch run on?
A: Hardware:
   * Hardware version 2 (TI-89 HW2, TI-92+ HW2, Voyage 200)
   * Hardware version 3 (TI-89 Titanium)
   Software: Any AMS version between (and including) 2.00 and 3.00.

Q: How do I run the HW3Patch?
A: Send hw3patch.89z to your calculator, type hw3patch() and press [ENTER].

Q: How does it work?
A: It disables the RAM execution protection and modifies the AMS to make this
   permanent.

Q: OK, but how EXACTLY does it work?
A: In technical terms, it:
   1. disables the FlashROM and I/O port protection (do NOT ask me how to do
      that!)
   2. zeros out the ports at 0x700000-0x700007
   3. zeros out the initializers for 0x700000-0x700007 in the function 15 of the
      trap 11
   4. zeros out a check in the function 15 of the trap 11 which makes it fail
      when called from the trap 4 and thus causes a crash when changing the
      batteries with a TSR installed

Q: Will you release the source code of HW3Patch?
A: No, sorry. I MIGHT send it to trusted people who give me really good reasons
   why this might be a good idea, but generally the answer will be "no". The
   reason for this is that the methods for disabling the FlashROM and I/O port
   protection are a closely-guarded secret, because that protection is the only
   one stopping you from writing a program which makes the calculator
   PERMANENTLY UNBOOTABLE.

Q: After running the HW3Patch, can I still send my copy of AMS to another
   calculator?
A: NO, UNLESS you are using the TIB Receiver on the receiving calculator. You
   CAN however RECEIVE an AMS update, and doing so will uninstall the HW3Patch
   and allow you to send your copy of AMS again (until you run HW3Patch again).

Q: How can I uninstall the HW3Patch?
A: You need to send a fresh copy of the AMS operating system. This will
   overwrite the patched AMS with a clean version.

Q: Can I switch from h220xTSR to HW3Patch on my HW2 calculator?
A: Yes, the HW3Patch can "upgrade" h220xTSR installations. The only caveat is
   that, in order to be able to uninstall h220xTSR's trap 4 hook, there must not
   be any keyboard accelerators, password programs or similar trap 4 TSRs (i.e.
   memory-resident programs which are executed whenever the calculator is turned
   on or off) installed. Otherwise, you will get an "ERROR: Unknown trap 4
   hook", which means you need to temporary uninstall the aforementioned types
   of TSRs.

Q: Can I switch from HW2Patch to HW3Patch on my HW2 calculator?
A: Yes, the HW3Patch can upgrade both RAM-resident and FlashROM-resident
   installations of the HW2Patch. The result will always be a FlashROM-resident
   HW3Patch installation. The advantage of doing this is that you will no longer
   get crashes when you change your batteries.

Q: Is the HW3Patch dangerous?
A: There is always a risk involved with disabling the FlashROM and I/O port
   protection, but I really do NOT think the HW3Patch is going to harm your
   calculator in any way. However, please keep in mind that this is NOT a
   legally binding promise, and that I can IN NO EVENT be held legally
   responsible for any type of damage (see the license terms).

Q: Where can I contact the author?
A: Web page: http://members.chello.at/gerhard.kofler/kevin/ti89prog/
   E-mail: kevin.kofler@chello.at or Kevin@tigcc.ticalc.org