Pi zero with Hyperpixel4 no image

Support
1

I have loaded the “recommended” OS using rpi-imager which is Debian Bullseye legacy 32bit and modified /boot/config.txt to have the line dtoverlay=vc4-kms-dpi-hyperpixel4. I can ssh into the pi zero w with no problem, and it can access the network and outside world fine, but the screen is always black. Is there some program I can run which will force a test to see if the pi can tell if the screen is out there?

The uncommented portion of config.txt is the following. I did comment out the search for DSI display because this is a dpi display, but it didn’t work before I did that either.

Enable audio (loads snd_bcm2835)

dtparam=audio=on

Automatically load overlays for detected cameras

#camera_auto_detect=1

Automatically load overlays for detected DSI displays

#display_auto_detect=1

Enable DRM VC4 V3D driver

dtoverlay=vc4-kms-dpi-hyperpixel4
#dtoverlay=hyperpixel4
#dtparam=rotate=90
#max_framebuffers=2

Disable compensation for displays with overscan

#disable_overscan=1

[cm4]

Enable host mode on the 2711 built-in XHCI USB controller.

This line should be removed if the legacy DWC2 controller is required

(e.g. for USB device mode) or if USB support is not required.

otg_mode=1

[all]

[pi4]

Run as fast as firmware / board allows

arm_boost=1

I’m assuming I missed a step some where. I did double check that all the header pins are well soldered though. I have a nice 'scope - so if there are pins I can monitor to help troubleshoot I’m happy to dig into that too.

2

I ran the legacy command “curl -sSL https://get.pimoroni.com/hyperpixel4 | bash” and that changed config.txt to include

overscan_left=0
overscan_right=0
overscan_top=0
overscan_bottom=0
enable_dpi_lcd=1
display_default_lcd=1
display_rotate=0
dpi_group=2
dpi_mode=87
dpi_output_format=0x7f216
hdmi_timings=480 0 10 16 59 800 0 15 113 15 0 0 0 60 0 32000000 6

I changed display_rotate=0 to display_rotate=90 and it flipped the screen 180 degrees. At 180, it was normal. I tried the DISPLAY=:0.0 hyperpixel4-rotate left and that did not do anything. I then tried display_rotate=1 in config.txt AND IT WORKED! So now I can get this project going the way it was meant to. Hopefully this will help anyone else that attempts to connect a Pi Zero to a Hyperpixel display.