Hey there, let's troubleshoot that annoying black screen issue you're hitting after adding your custom device /device/my_company/my_product/ to Android 6.0.1_r46 Marshmallow. Since your default full-eng build works fine, the problem is almost certainly in your custom device configuration—let's break down the most likely culprits and fixes:

1. 检查BoardConfig.mk的核心硬件配置 #

This file is the backbone of your device setup, so double-check these critical flags:

• Kernel配置: If you're using the emulator's prebuilt kernel (which you should for emulated devices), make sure you have:

  TARGET_PREBUILT_KERNEL := prebuilts/qemu-kernel/x86/kernel-qemu
  

  (Adjust the path to match your target architecture—x86_64, arm, etc.) Missing this or pointing to a mismatched kernel will cause the emulator to hang on boot.
• CPU ABI匹配: Ensure TARGET_CPU_ABI and TARGET_CPU_ABI2 match the architecture you're building for. For example, the default full-eng build uses x86, so if your device is set to armeabi-v7a without proper emulator support, it'll fail to load.
• 模拟器必需的硬件标识: Add these flags to enable emulator-specific hardware support:

  BOARD_USES_QEMU_HARDWARE := true
  TARGET_USES_QEMU := true
  

2. 验证产品配置文件（my_product.mk/AndroidProducts.mk） #

Your product needs to inherit emulator-specific configurations to load properly:

• 继承基础模拟器产品：

  $(call inherit-product, $(SRC_TARGET_DIR)/product/emulator.mk)
  $(call inherit-product, $(SRC_TARGET_DIR)/product/core_minimal.mk)
  

  Without these, you'll miss critical emulator services like qemu-props which handle hardware parameter passing.
• 检查PRODUCT_PACKAGES：Make sure you include emulator-essential components:

  PRODUCT_PACKAGES += \
      emulator-properties \
      qemu-props \
      libqemu_trace
  

3. 查看启动日志定位卡住的环节 #

A black screen doesn't mean nothing's happening—let's get logs:

• 启动模拟器时加内核日志参数：

  emulator -avd your_custom_avd -show-kernel
  

  This will print kernel boot logs directly to your terminal. Look for errors like "failed to mount rootfs" or missing driver modules.
• 如果能连接ADB（有时候即使黑屏ADB能连上），抓取系统日志：

  adb logcat -b all
  adb shell dmesg
  

  Common red flags: SELinux denials, missing HALs, or system services crashing on startup.
• 临时关闭SELinux测试：Add androidboot.selinux=permissive to your emulator's boot arguments. If the system loads, you need to fix your device's SELinux policy (add proper rules in /device/my_company/my_product/sepolicy/).

4. 检查自定义设备的Makefile语法 #

You mentioned a partial Android Mk snippet—make sure the device filtering logic is complete and correct:

ifneq ($(filter my_product, $(TARGET_DEVICE)),)
# Your device-specific rules here
endif

A missing closing endif or typo in TARGET_DEVICE can silently skip your device's configuration, leading to an incomplete build that boots to black screen.

5. 确认AVD配置正确性 #

• When creating your AVD, explicitly select your custom device (my_product) instead of a generic one.
• Verify the AVD's RAM allocation is at least 512MB (Marshmallow needs this minimum to boot properly).
• Ensure the AVD is using the system image from your custom build, not a leftover default image.

内容的提问来源于stack exchange，提问作者SK17