Well, before you do it, you could try putting in new batteries if you haven't already, and try to enter the emergency OS update mode...

So I forgot how to enter the OS update mode, and I have already tried new batteries.

Yeah, email John Anderson. He is the person I have had the best luck with.

http://www.casioeducation.com/support/contact

Ok thanks to both of you for your help. I will post any questions I have if I have any.

*edit*
Just for confirmation the emergency OS update did not work.

I don't think it is a ROM issue. Did those people overclock their machines?

I didn't overclock mine ever. I was just computing some numbers and turned it off, but it stayed on the exit screen.

Did you use some specific add-ins? Have you been programming for the Prizm?

The fact that it stayed on the "Casio" screen was what made me think about flash corruption... since when the calculator turns off, it writes its current state to flash, and that step could be failing or operating improperly (i.e. modifying the wrong flash access).

EDIT: I sure hope it's not a problem caused by my Utilities add-in. I already reverted all the changes that killed my calculator, both on the source code of Utilities and on my build environment (crt0.S, etc.), and I've triple-checked that the add-ins compiled from that time on, do not mess with RS memory at all.
Do you have MPoupe's Doom port installed? It's the only add-in I know of, that abuses the RAM (using things that are allocated to the "main" process) and reads files from flash directly (skipping Bfile_ReadFile).

What do you mean specific?

I haven't programmed for about a week.

@gbl08ma
This also happened a few times on my Prizm, but pressing a button will turn it off.

@krazylegodrummer56
I'm just asking if you are a normal Prizm user who did not use custom add-ins or have been programming some of these. It seems weird because the average Prizm user does not seem to break their machine.

You mean that when it stays waiting for a key to be pressed in order to really turn off, it's actually failing the flash backup?!? Ugh, that has happened uncountable times to me and my friends...

krazy, what OS version did you have installed?

I don't think it is utilities, because when my calc broke utilities didn't even exist.

The thing here is, that there's a very high chance my calculator broke due to messing with the RS memory at the wrong location, at the wrong time. It could be possible that public versions of Utilities also killed calculators, if I had not taken the care of reverting every change in my build environment that allowed me to build such a serial-killer add-in (btw, the "kill" would result in the deletion of the bootloader serial number...).



I would say the average user doesn't use its calculator for as many hours/day as some of us do... assuming all calculators have the same probability of breaking, a heavier usage will increase the likeliness that it will break - as with all the electronics... so we will see more broken calculators between heavy users.

I once killed one of my Prizms by pressing the RESTART button while being in the test mode's Message Check menu (which doesn't do anything dangerous, but also messed around with the boot code).

Consider the RESTART circuit to be problematic.
(And they did not change anything in the latest hardware revision)
So you better remove the batteries when the OS hangs.

I kept on thinking I should have used the "restart" button instead... and after all this time I discover I had been doing it right!

Just to clarify, software reboots (such as those that happen when you press Exit on a system error, or when you call the appropriate syscall) don't suffer from the problems in the reboot circuitry, do they?

I'm no expert, but I guess the difference is that pressing RESTART instantly resets the MPU whereas pulling the batteries won't (at least there is a difference between power-on reset and manual reset).

On hardware revision 02 (very early models) there is a quite large resistor missing near the flat cable's Vcc pins. This resistor is only present on 58 MHz models.

2.0

What models don't run at 58 MHz?

All, except Prizm and ClassPad II.

That is, the fx-9860GII, fx-9750GII, fx-7400GII and ClassPad 330 Plus with the SH7305 run at 29 MHz.