How to Upgrade the fx-9750GII to fx-9860GII (Natural Display) for FREE

I've just finished my second year of A-Levels, and I remember when starting we were encouraged to get a Casio Calculator that was capable of solving definite integrals. If you're anything like me, you bought the cheapest one you could and got the fx-9750GII rather than the model up (9860GII)...

This thing looks like electronics from the 80s, and the software definitely seems that way too. The thing that bugged me was that you can't make vertically stacked fractions, the powers don't appear on top of the numbers and answers can only appear in decimals, not in roots or fractions. These are serious disadvantages in tests and a pain in the arse!

Luckily, I found out a fix. This is that you can put the model up's firmware (9860GII) onto the 9750GII, and it works exactly like a 9860GII. This gives it 'Natural Display' and fixes all the annoyances I mentioned prior.

Before the upgrade (No natural display)
After the upgrade (With natural display!)

There are potential risks associated with this process, so follow instructions carefully. This only works for GII models, not G models.

For this required you need:

  • A fx-9750GII (Duh)
  • A Mini-USB to USB Cable (£1.59 on Amazon)
  • A Windows PC with Windows 7/8/10.
  • 30 minutes at most

Finding the Calculator's version

For these instructions, there are two slightly different procedures depending on your calculator version, so we must find the current version before starting.
On your calculator, press Menu, then System, then press F4 (Version). Write down the numbers highlighted in red.
  • If these numbers are 02.00.**** you must follow procedures for GII-1.
  • If these numbers are 02.01.****, 02.02.**** or any higher version you must follow procedures for GII-2.

Making a Backup of the current Software

There is a minimal risk something can go wrong during this process, my friend flashed the incorrect firmware to his calculator and everything appeared upside down! If we have a backup we can restore the calculator back to its original condition if anything goes wrong.
  1. Install Casio Program Link Software (FA-124). This is required to be installed for your computer to be able to 'talk' to the calculator. This is downloaded here
    Once downloaded, open the .zip file and double click the installer file and proceed with the installation.
  2. Download from here, open the zip and open 'fxBackup_205.exe'. Sometimes a Windows Defender warning pops up, click 'More info' and then 'Run anyway' - I promise that it's not a virus and a false-positive. 
  3. Now we need to put the calculator in 'BIOS' mode. This is a little tricky at first, so these are the steps:

    * Press F2 + 4 + AC/on + RESTART simultaneously
    * Release RESTART, leaving your fingers on F2 + 4 + AC/on
    * Release F2 + 4 + AC/on, and quickly press 9 and X simultaneously.

    This scary looking screen should show up, but don't worry, this is intended.
  4. Connect the calculator to your PC with the Mini-USB Cable and the PC's USB port.
  5. Ensure FA-124 is closed if open.
  6. In fxRemote, press 'Backup flash' and select a safe location on your PC to hold this backup for the rest of the tutorial. This will take about a minute to complete.
    Now everything's backed up! Nothing on your calculator has been changed yet, so if you have cold feet you can just press 'RESTART' on your calculator and quit now - or carry on if you're ready to get the fancy new firmware.

Flashing the Firmware

Now that we're all safe with our backup, we can get into the interesting bit.
First we need to download a specific folder of stuff depending on that version number we found at the beginning.

If you have a GII-1 Calculator: 

  1. Go here and download the 'pfxRecover - GII-1' folder by pressing the circle in the top right of the folder and pressing Download.
  2. Ensure FA-124 is closed if open.
  3. Extract and open the folder and run 'pfxRecover_BETA.exe'
  4. Put your calculator into BIOS mode in the same way as in the last stage.
  5. Press 'Recover', upon pressing this you will need to browse for a file...
    The file to use must have the same first numbers as your original version, so since your version was '02.00.****' you should open '2_00_0200.fls'
  6. This process will take about 2-3 minutes to complete. Do not disconnect the cable, close pfxRecover or turn off your computer or calculator.
    If something went wrong, or you want to go back to the old firmware, just follow the same steps but instead of selecting 
    '2_00_0200.fls', select the backup you made in the last stage.
If you have a GII-2 Calculator:
  1. Go here and download the 'fxRemote - GII-2' folder by pressing the circle in the top right of the folder and pressing Download.
  2. Ensure FA-124 is closed if open.
  3. Extract and open the folder and run 'fxRemote.exe'
  4. Put your calculator into BIOS mode in the same way as in the last stage.
  5. Press 'Recover flash', upon pressing this you will need to browse for a file.
  6. The file to use must be correct for your version of calculator: 
    1. If your version is '02.0*.0200' you should open '2_01_0200_sh3.fls'
    2. If your version is '02.0*.0201' you should open '2_02_0201_sh4.fls'
      These files are contained in the 'fxRemote -GII-2' folder.
  7. Press OK on the prompt to begin flashing, this process will take about 2-3 minutes to complete. Do not disconnect the cable, close pfxRecover or turn off your computer or calculator.

    If something went wrong, or you want to go back to the old firmware, just follow the same steps but instead of selecting the same .fls files, select the backup you made in the last stage.


After completion, your calculator should start up normally but have the features of a 9860GII! Congratulations!

Enjoy being able to stack fractions, have powers float above the number and getting answers as surds or fractions instead of decimals to name a few of the improvements - plus you got a better calculator for a cheaper price!


  1. Thank you for this great tutorial. I now enjoy calculating natural fractions.

    1. Thanks for the response. I'm happy it worked out for you!

  2. Want the 9860GII cause of the included spreadsheet program (unavailable on 9750GII). Will it give me that too? Is it literally a 9860GII firmware straight loaded onto the lower end model? Or only the features you mentioned hacked into a firmware file?

    1. It's literally the original unedited 9860GII firmware, so if that feature is on the 9860GII then you're set.

  3. How do you actually get the 9860GII file on your PC to transfer to your calculator?

    1. See the download links in the post.

    2. Yes but when I downloaded the “2_00_0200.fls, it said that there was nothing it could open in, and I couldn’t find it in pfxRecover when I clicked recover, so I don’t know how to do it.

  4. Thanks so much! Worked out great

  5. So when performing the backup, it says to wait until the calculator says "waiting" but all the calculator says is "unknown bios" Have you ran I to this issue at all?

    1. A bit late, but you want to use version "fxBackup_204". See here:

  6. Hey there,

    Do you happen to have files for OS ver 2.04...?

  7. I tried downloading the fxBackup file through the link, but it keeps sending me to this music place after I click download, and no file with that name has been downloaded to my computer

    1. Hi,
      Thanks for letting me know. I've updated the link for fxBackup.

  8. I’ve tried and got to the final step and it said successful but my calculator won’t turn on now. Any solutions?

    1. Hi Sam, this is the first time I've heard of this happening. I would suggest repeating the steps of entering BIOS mode and putting the backed up file onto the calculator again.

    2. Nice one! Thanks a lot for this. It worked beautifully.

    3. did u find any solution for that?

  9. Hey, I tried it but it wont work for me. When i click on the fxbackup_205 it opens and when i go to backup flash i click save and then it automatically cancels saying:

    i00:00:00.118:USB communication failed: check USB-driver or cabling.
    00:00:00.118:Check if FA-124 is correctly installed on this machine.

    I purchased the cable you recommended so that should be fine.
    Everytime i click on the FA-124 program in my documents it keeps redownloading I dont know what is wrong with it.
    Are there any solution you know to deal with this?

    1. This error means, for whatever reason, your computer cannot connect to the calculator.
      I'd recommend trying the whole process again from the beginning, it sounds like perhaps your FA-124 driver didn't install correctly. Maybe trying it again on a different computer will work.
      Good luck :)

  10. it worked well for a while but now my calculator doesn't show anything like dead !.. when I try to re flash the software it works and I also managed to connect it to fa-124 by pressing f1 once connected with pc.. but still nothing shows up on the calculator screen any idea what may be the problem help plz!

    1. Hi, it's strange that it worked for a while (as this would indicate the flash was successful) and then stopped working.

      If nothing is displaying, it's possible the batteries are low, or maybe the calculator is faulty independently of the flashing.

      This behaviour isn't something I've heard of or experienced before I'm afraid.

    2. actually it worked flawlessly and I was able to even use and enjoy the eactivity feature but suddenly after a while of not using it this happened . I kept doing the same steps of restarting and getting to bios and it worked !! ... and I kept using it .. I left 2 days on my desk and suddenly it happened again ! .. maybe it is a hardware issue? I have no clue. I changed the batteries with brand new ones with no success :(

    3. When I started the flashing on first time it gives me 2 messages " it seems that the hard ware is gII " the second warning is that " unknown hardware .. flash device: 000000A8 ,, flash manufacturer: 000000C2" .... this is normal right? and if u please have a back up for 2.04 can u email it to me on ""

    4. can u send me ur back up please? I won't to flash back to the original software and I lost it bec I did it long time ago

    5. Hi, I'm not sure whether it is possible to restore another calculator's backup, however I am happy to share my backup for you to attempt it if you have no other option.

      I originally did this on a calculator running 02.01.0700 in 2017.

      My backup file can be downloaded here:!AkkqgrVtiHK3gYl7PF5jabfNgyHCUQ

      Please let me know if this is successful. I hope it works for you.

  11. if u please have a backup os fro gII 2.04 can u send it to this Email:

  12. Man, I LOVE YOU...
    My old calculator returns to life. Thank you so much.
    THANK YOU!!!!

  13. thx a lot i just wanted to know if it is possible to update the os system currently i have 02,01,0200 bu ti need 02,04 or higher


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