K4 Kindle 4 serial port problem

hanalee · 12-08-2018, 10:38 AM

I have two problems.

One is that the Kindle 4 will not boot.
The screen is frozen and the computer is disconnected.
I have a serial port connection and this is the log file.
What is the problem?

Spoiler:

Another problem is that keyboard input is not available on the serial port.
So I can not get into u-boot.
The current values are tx 3.26v, rx 1.97v.
Why does not keyboard input work?

knc1 · 12-08-2018, 11:27 AM

The Kindle's virtual keyboard is not suppose to be operated from the serial port or to be available on-screen.

The serial port input from your terminal emulator is the only input device.
The serial port output to your terminal emulator is the only output.

- - - - -

Most likely problem: User error.

See the section you posted:

Code:

Press [ENTER] for recovery menu... 
0 /ERROR:gasgauge_battery_id_valid: No battery found
ERROR:
=== BATTERY ID IS INVALID. STOPPING BOOT ===

Does not show you ever pressed "Enter" and is pretty explicit in why the boot process halted.

hanalee · 12-08-2018, 12:32 PM

Thank you for answer.
My description was not enough.
The keyboard is the pc keyboard.
I have rebooted the Kindle. I tried to enter the u-boot menu by pressing the pc keyboard key.
But the keystroke did not work.
The serial port connection was made by soldering.
The voltage of the wire connected to the serial port is normal.
What is the problem?

Is it a battery problem that Kindle does not boot ...
But the charge is enough. The battery voltage is 4.17V.
Is the battery broken ...?

12-08-2018, 11:27 AM	#2
knc1 Going Viral Posts: 17,212 Karma: 18210809 Join Date: Feb 2012 Location: Central Texas Device: No K1, PW2, KV, KOA	The Kindle's virtual keyboard is not suppose to be operated from the serial port or to be available on-screen. The serial port input from your terminal emulator is the only input device. The serial port output to your terminal emulator is the only output. - - - - - Most likely problem: User error. See the section you posted: Code: Press [ENTER] for recovery menu... 0 /ERROR:gasgauge_battery_id_valid: No battery found ERROR: === BATTERY ID IS INVALID. STOPPING BOOT === Does not show you ever pressed "Enter" and is pretty explicit in why the boot process halted. Last edited by knc1; 12-08-2018 at 11:30 AM.

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12-08-2018, 12:32 PM	#3
hanalee Member Posts: 12 Karma: 12 Join Date: Jul 2018 Device: kindle pw3	Thank you for answer. My description was not enough. The keyboard is the pc keyboard. I have rebooted the Kindle. I tried to enter the u-boot menu by pressing the pc keyboard key. But the keystroke did not work. The serial port connection was made by soldering. The voltage of the wire connected to the serial port is normal. What is the problem? Is it a battery problem that Kindle does not boot ... But the charge is enough. The battery voltage is 4.17V. Is the battery broken ...?

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