HP Prime bricked after update

[XY0797]

(06-24-2021 02:31 PM)rprosperi Wrote:  It is still difficult to understand, due to translation challenges, though we understand you are trying your best to explain.

You mention "damage to flash" many times, caused by the f/w. Why do you think it is damaged, what evidence of damage so you see, what are the precise symptoms? What exact steps do you follow and what are the results?

Without exact information, it isn't possible to narrow down the cause, so these details are needed to understand cause and possible solutions.

Also, have you tried to re-format the flash using the diagnostic menu?

Okay, let me explain my logic now.
The calculator is broken without warning and no damage process is visible. Its screen, keyboard, functions and recovery mode are normal until it is damaged.I realized it was broken when I tried to open the calculator and it didn't respond.I tried various ways to force a reboot, but it didn't work.I think it might be a problem with the screen or keyboard, and if it is, it should be able to connect to the computer after pressing the RESET key, but that doesn't work, so it's not a problem with the keyboard or the screen (the battery problem is excluded by me using the voltmeter).
I then tried to enter the recovery mode and the "factory-new" technology, but the screen was always black.
Therefore, there are only four possibilities left: ①Flash memory chip damage②CPU damage③Memory damage④Capacitance, resistance, triode, inductance and so on damage
Because three days before the accident, I upgraded the firmware for the calculator, and the only thing that the firmware can damage is the flash memory chip. Therefore, I think the flash memory chip is the most likely to be damaged, so I made a conclusion.
I tried this technique, but it didn't work. I was desperate. Verification ②③ can only replace the corresponding chip. I don't have the relevant equipment. If I buy the equipment and can't repair it, it's expensive and risky. I'm a student without a job, and I don't want to verify ②③. Because there is no circuit diagram, I can't verify ④.
Thank you very much. I'm forced to stop repairing the calculator now because I'm preparing for the exam and it will take about five days.