EMM200 Patch for 2MB HP200LX

This is a patch information for EMM200.EXE(Ver.2.00), provided by Naohiko Shimizu. All information on this page are subject to absolutely no warranty. You can apply this patch only for HP200LX/2MB model with a 16Mbit DRAM chip in it. Following steps show the way to make patched version of EMM200.EXE.

If and only if your HP200LX's DOS BIOS data (0040:00c8-0040:00cb) are "08 00 00 00" , you can use this patch. Otherwise you must not use this patch. For people with 200LX/4MB model, I am preparing another patch. It works fine for my 200LX, but because a lack of configuring program it is still not available publically. Who owns RAM upgraded 200LX should contact to his dealer. They cannot be supported by my patches.

  1. Check compatibility.
    1. You can check this data with following steps
      1. Push ctrl+123 buttom so as to start DOS session
      2. type exactly as followings
        • debug
        • d0040:00c8,cb
        • q
      1. The data will be shown, check it.
      2. exit DOS session with exit command
  1. Applying patch.
    1. prepare EMM200.ZIPVer.2.00
    2. Extract archive on some PC (it can be 200LX also).
    3. Rename EMM200.EXE as EMM200.BIN by" REN" command of DOS.
    4. Issue DEBUG command from prompt, as debug emm200.bin
    5. enter following commands.
    6. Rename EMM200.BIN as EMM200.EXE.
    7. Transfer the programs in the archive and patched EMM200.EXE to 200LX.
    8. Install as usual EMM200

    Now you can use some DOS program which uses EMS. If you cannot get enough EMS pages, try to initialize C: drive with Ctrl-Shift-ON reboot.