Nothing but backlight using 4DCAPE43-T on Beagle

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1

hi

I was previously using a version of the IOT (non gui image) which was able to give me a command line interface. (see: https://groups.google.com/forum/#!category-topic/beagleboard/beaglebone-black/3Ffp74qhveQ). I’ve installed the latest version of Debian LXQT (9.4) from the official website, loaded it onto a microSD card and now booted it (with SD card in and the LCD screen attached). The output on the screen is now a backlit black screen. The LCD’s onboard LEDs (power and user) are a solid green ‘on’ and the beagle itself has its heartbeat LED pulse. There is no linux logo or any type of interface, only backlight. Same results using a 5VDC Jack. A picture is attached.

With the screen disconnected, I am still able to use PuTTY to connect to the beagle and display the current image (pic attached).

Do you have any idea what’s happening?

please save me.

backlight.JPG

hostnamel.png

2

sudo /opt/scripts/tools/version.sh

Regards,

3

(through putty, without LCD)

4

Your old version of u-boot in the eMMC is blocking overlays from
working properly..

Just run:

sudo dd if=/dev/zero of=/dev/mmcblk1 bs=1M count=10

and shutdown/reboot..

Then u-boot will auto-detect the LCD and pass the proper overlay to
the kernel. You should see the LCD come up early with a linux mascot
showing up..

Regards,

5

It works now!!!

Words cannot express my gratitude. Thank you thank you thank you for the help. Keep up the good work.

All the best,
-J

6

Robert:

Just for information …
What does the date/version of the bootloader in the eMMC need to be (or later than) so that this does not happen?

Thanks,
— Graham

7

Well, our patched u-boot: 2018.03

Which currently detects this list of LCD's and will correctly pass the
correct overlay to the kernel..

BB-CAPE-DISP-CT4-00A0.dtbo
DLPDLCR2000-00A0.dtbo
BB-BONE-NH7C-01-A0.dtbo
BB-BONE-LCD7-01-00A3.dtbo
BB-BONE-4D5R-01-00A1.dtbo
BB-BONE-4D4R-01-00A1.dtbo
BB-BONE-4D4N-01-00A1.dtbo
BB-BONE-4D4C-01-00A1.dtbo
BB-BONE-4D7N-01-00A1.dtbo
BB-BONE-4D7C-01-00A1.dtbo
BB-BONE-4D5N-01-00A1.dtbo
BB-BONE-4D5C-01-00A1.dtbo
BB-BONE-4D7R-01-00A1.dtbo
BB-BONE-LCD4-01-00A1.dtbo

If i'm missing one, either i don't have it or, something...

Soon we will transition to 2018.07 to get the spectre/meltdown fixes,
but overlay support is the same as 2018.03.

(dealing with one odd bug in 2018.07)

Regards,