Can't turn off calculator

[lnex_x]

Shift + On no longer turns my HP Prime off. Now when I had to use it this evening, I found the entire keyboard didn't work except for Shift and ALPHA, but I fixed that by reverting to Firmware version 20181016; I had been using the latest version. However, I still can't turn it off. I tried following this document: http://www.hp-prime.de/files/composite_f...y_mode.pdf to reset it via recovery mode (clearing memory doesn't help), but the screen goes black and nothing comes up despite waiting for a full minute. I've also tried removing the battery for an hour.

Please help, thank you.

[Joe Horn]

Sometimes this condition can be exited by putting the Prime into "coma mode" (N.B. that's COMA, not COMMA). With the calculator turned on, press and hold down the Shift key, then (while still holding down the Shift key) press and hold down the On key for at least one full second, then release both.

Turning on from coma mode takes about three seconds; just press On and be patient. Afterwards, turning off and on should be like normal.

This was a known bug in some firmware updates in the . The bug is activated by exiting the C+F+O diagnostic screen by pressing 9. Don't do that; exit instead by pressing C.

Please let us know whether the above helps or not.

[lnex_x]

That makes the calculator freeze, not even the touch screen works, but it doesn't turn off. Now pressing On from that state causes the screen to flash black then white, but it returns to how it was (normal, but still can't turn off). So it's like disabling inputs, not coma mode. The other methods still don't work after that.