official 7" touchscreen display not working

hi, i am quite new to this (raspi, not android)...so i just followed your instructions...but the device never booted up (neither with your pre-built zip, nor with my self compiled version....though, i am using the official 7" display, not the one you are using... anyway, i supposed the issue might have been, the raspberrypi-ts.ko not being loaded...so i made it built-in by changing the config: CONFIG_TOUCHSCREEN_RASPBERRYPI_FW=y (was m before). since it still didn't boot up, i decided to buy the breakout board to debug this...and here we are now:

01-01 00:00:06.531   310   310 F DEBUG   : *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
01-01 00:00:06.532   310   310 F DEBUG   : Build fingerprint: 'SnappAutomotive/snapp_car_rpi4/rpi:11/RQ3A.210705.001/eng.domini.20210730.130023:userdebug/test-keys'
01-01 00:00:06.532   310   310 F DEBUG   : Revision: '0'
01-01 00:00:06.532   310   310 F DEBUG   : ABI: 'arm64'
01-01 00:00:06.532   310   310 F DEBUG   : Timestamp: 1970-01-01 00:00:06+0000
01-01 00:00:06.532   310   310 F DEBUG   : pid: 224, tid: 224, name: android.hardwar  >>> /vendor/bin/hw/android.hardware.graphics.composer@2.1-service.rpi4 <<<
01-01 00:00:06.532   310   310 F DEBUG   : uid: 1000
01-01 00:00:06.532   310   310 F DEBUG   : signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x0
01-01 00:00:06.532   310   310 F DEBUG   : Cause: null pointer dereference
01-01 00:00:06.532   310   310 F DEBUG   :     x0  0000000000000000  x1  00000076369ff120  x2  00000060a74889cf  x3  0000000000000003
01-01 00:00:06.533   310   310 F DEBUG   :     x4  0000000000000000  x5  0800401010020000  x6  0000000000000000  x7  7f7f7f7f7f7f7f7f
01-01 00:00:06.533   310   310 F DEBUG   :     x8  0000000000000000  x9  0000000000000000  x10 0000000000000000  x11 0000000000000000
01-01 00:00:06.533   310   310 F DEBUG   :     x12 000000000000000b  x13 ffffffffffffffff  x14 0000000000000001  x15 ffffffffffffffff
01-01 00:00:06.533   310   310 F DEBUG   :     x16 00000076360969e8  x17 00000076360245a0  x18 00000076374d2000  x19 b4000076367ee028
01-01 00:00:06.533   310   310 F DEBUG   :     x20 b4000076367c8180  x21 0000000000000000  x22 0000007636b18000  x23 0000000000000000
01-01 00:00:06.533   310   310 F DEBUG   :     x24 0000000000000000  x25 0000000000000000  x26 0000000000000000  x27 0000000000000000
01-01 00:00:06.533   310   310 F DEBUG   :     x28 0000000000000000  x29 0000007fc25aeaf0
01-01 00:00:06.533   310   310 F DEBUG   :     lr  00000060a748b7dc  sp  0000007fc25aea70  pc  00000060a748bb40  pst 0000000080000000
01-01 00:00:06.551   310   310 F DEBUG   : backtrace:
01-01 00:00:06.551   310   310 F DEBUG   :       #00 pc 0000000000009b40  /vendor/bin/hw/android.hardware.graphics.composer@2.1-service.rpi4 (android::hwc_context::init_with_connector(android::kms_output*, _drmModeConnector*)+1288) (BuildId: 3ab485b68085835d2fba59a7cbfa8375)
01-01 00:00:06.551   310   310 F DEBUG   :       #01 pc 0000000000009eb0  /vendor/bin/hw/android.hardware.graphics.composer@2.1-service.rpi4 (android::hwc_context::init_kms()+616) (BuildId: 3ab485b68085835d2fba59a7cbfa8375)
01-01 00:00:06.551   310   310 F DEBUG   :       #02 pc 0000000000009f68  /vendor/bin/hw/android.hardware.graphics.composer@2.1-service.rpi4 (android::hwc_context::hwc_context()+112) (BuildId: 3ab485b68085835d2fba59a7cbfa8375)
01-01 00:00:06.551   310   310 F DEBUG   :       #03 pc 000000000000a0fc  /vendor/bin/hw/android.hardware.graphics.composer@2.1-service.rpi4 (android::Hwc2Device::Hwc2Device()+124) (BuildId: 3ab485b68085835d2fba59a7cbfa8375)
01-01 00:00:06.551   310   310 F DEBUG   :       #04 pc 000000000000c068  /vendor/bin/hw/android.hardware.graphics.composer@2.1-service.rpi4 (android::hardware::graphics::composer::V2_1::implementation::ComposerHal::ComposerHal()+64) (BuildId: 3ab485b68085835d2fba59a7cbfa8375)
01-01 00:00:06.552   310   310 F DEBUG   :       #05 pc 00000000000112c8  /vendor/bin/hw/android.hardware.graphics.composer@2.1-service.rpi4 (android::hardware::graphics::composer::V2_1::implementation::Composer::Composer()+88) (BuildId: 3ab485b68085835d2fba59a7cbfa8375)
01-01 00:00:06.552   310   310 F DEBUG   :       #06 pc 0000000000011fec  /vendor/bin/hw/android.hardware.graphics.composer@2.1-service.rpi4 (main+244) (BuildId: 3ab485b68085835d2fba59a7cbfa8375)
01-01 00:00:06.552   310   310 F DEBUG   :       #07 pc 00000000000854b4  /apex/com.android.runtime/lib64/bionic/libc.so (__libc_init+108) (BuildId: a262aead45d9f1c62982589f85c1715e)

stack tool encodes this to:

Stack Trace:
  RELADDR           FUNCTION                                                                                                                                                                                                            FILE:LINE
  v-------------->  android::find_mode(_drmModeConnector*)                                                                                                                                                                              hardware/arpi/graphics/composer/2.1/drm_kms_v3d.cpp:494
  0000000000009b40  android::hwc_context::init_with_connector(android::kms_output*, _drmModeConnector*)+1288                                                                                                                            hardware/arpi/graphics/composer/2.1/drm_kms_v3d.cpp:549
  0000000000009eb0  android::hwc_context::init_kms()+616                                                                                                                                                                                hardware/arpi/graphics/composer/2.1/drm_kms_v3d.cpp:640
  0000000000009f68  android::hwc_context::hwc_context()+112                                                                                                                                                                             hardware/arpi/graphics/composer/2.1/drm_kms_v3d.cpp:665
  v-------------->  std::__1::__unique_if<android::hwc_context>::__unique_single std::__1::make_unique<android::hwc_context>()                                                                                                          external/libcxx/include/memory:3132
  000000000000a0fc  android::Hwc2Device::Hwc2Device()+124                                                                                                                                                                               hardware/arpi/graphics/composer/2.1/Hwc2Device.cpp:35
  v-------------->  std::__1::__unique_if<android::Hwc2Device>::__unique_single std::__1::make_unique<android::Hwc2Device>()                                                                                                            external/libcxx/include/memory:3132
  000000000000c068  android::hardware::graphics::composer::V2_1::implementation::ComposerHal::ComposerHal()+64                                                                                                                          hardware/arpi/graphics/composer/2.1/ComposerHal.cpp:32
  v-------------->  std::__1::__unique_if<android::hardware::graphics::composer::V2_1::implementation::ComposerHal>::__unique_single std::__1::make_unique<android::hardware::graphics::composer::V2_1::implementation::ComposerHal>()  external/libcxx/include/memory:3132
  00000000000112c8  android::hardware::graphics::composer::V2_1::implementation::Composer::Composer()+88                                                                                                                                hardware/arpi/graphics/composer/2.1/Composer.cpp:32
  0000000000011fec  main+244                                                                                                                                                                                                            hardware/arpi/graphics/composer/2.1/service.cpp:50
  00000000000854b4  __libc_init+108

any ideas/suggestions, what i might be missing?

android-rpi / device_arpi_rpi4

official 7" touchscreen display not working #78