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Nano pc t4 won't boot

Posted: Mon Oct 19, 2020 5:16 pm
by armpeggio
Hello everybody, i like this nanopc-t4 very much and it ran very good, i ran ubuntu from the eMMC drive.
Resently i messed it up, it will not boot from eMMC, it booted first from sd card but now it will not boot from that too.
I pushed the buttons, boot and recovery during startup, to start up from a sd-card that was not working so i pushed the buttons to see if that helped, but the problem got worse.
Please help me to fix this, is it now in recovery mode, or did i messed up some boot configuration??
Thanks in advance, Dian from the Netherlands

Re: Nano pc t4 won't boot

Posted: Wed Oct 21, 2020 7:55 am
by v8dave
Connect a debug cable to the T4 and see what is showing up in the output.

If you don't have one, get one, they are cheap and it will help to diagnose what is wrong.

The other option is to create a bootable SD image and hold down the BOOT button so that is boots from the SD card. If this doesn't work then you likely have a damaged board. What does the POWER and STATUS LED show?

Re: Nano pc t4 won't boot

Posted: Sat Oct 24, 2020 9:23 am
by armpeggio
Thanks for the reply.
Decided to install the friendlyDesktop ubuntu again from the sd-card with the eMMC-flasher tool.
Inside that program there is an option to exit and then you are asked if you will
Do: alt+F2 to enter tty2.
Is this the way to debug, what you suggested. And use a tx/rx cable and attach the usb to a competer and read the messages over incomming usb???
And what commands do you use then for debugging the nanopc-t4.
Then i can use that to debug.
Thanks, Dian

Re: Nano pc t4 won't boot

Posted: Sun Oct 25, 2020 5:35 am
by v8dave
To debug you connect to the header DBG UART on the edge of the board. With this you can see the debug output and also be able to type into this various linux commands as if you were using the terminal.

Note that the baud rate is 1,500,000 bps so you will need the use Putty to read this.

Any 3.3V TTL USB to Serial will work. Pinout in the Wiki.