Beagle Bone Black 4D Systems 4th Gen 4.3" LCD, could not request pin 40

I have flagged this under "Beagle Bone Black " but maybe its more of a CAPE issue.

I have a BBB Revision C, with 4DSystems LCD Cape.

I am hoping someone on this forum could possibly help with a software related issue.

I am running 2net 4.1 Kernal ,

The screen shows “Android” and then this fades out.

Looking at serial I have this error:

[ 3.353484] pinctrl-single 44e10800.pinmux: pin 44e108a0.0 already requested by panel; cannot claim for 0-0070
[ 3.363651] pinctrl-single 44e10800.pinmux: pin-40 (0-0070) status -22
[ 3.370239] pinctrl-single 44e10800.pinmux: could not request pin 40 (44e108a0.0) from group nxp_hdmi_bonelt_pins on device pinctrl-single

I think this might be why it doesn’t continue with the Kernal but I could be wrong.

Referring to all available forum posts regarding this LCD I have tried many different options in uEnv.txt to disable HDMI, disable universal cape and alike but nothing seems to work.
I am not sure what command options are actually relevant to this particular build.

I have also read that the boot int eh EMMC can also affect the overlays which are being loaded by the image in the SD card. I have ensured I have loaded one of the latest flasher images from official beagle bone site.
Running just this flasher image, the screen does display correctly so I know it is not a hardware related issue.

I have also double checked the overlay that is being used and all the pins are correct and match the schematic of the display.

I am a newbie to Beable Bone Black and Linux so this is incredibly difficult and have spent weeks now trying to overcome this hurdle.
So any help would be greatly appreciated.

I have attached the serial outputs from the problamatic SD image and also for my base EMMC.

Hoping someone could provide some info to push me in the right direction.

BBB_SerialOutput.txt (35.4 KB)

BBB_SerialOuputEMMC.txt (3.72 KB)


Just a couple points..

I don't use Android on these devices, thus i don't support it.. (My
Free time, is My free time. :wink: )

The 4.1.x-ti kernel used by:
was really just a preview release. All the refinement and u-boot
overlay enhancements were done on the: v4.4.x/v4.9.x/v4.14.x releases.

So feel free to swap out the 4.1.x-ti with either 4.4.x-ti or 4.14.x-ti..

With the move to u-boot overlays: the version of u-boot became VERY
important, the bootrom loads u-boot from the eMMC first.. So yeah, if
the version of u-boot doesn't support overlays is installed to eMMC
you have to nuke it. :wink: