Custom AOSP Vendor Image: SIM Card Not Detected After Flashing in Android 13 for Pixel 7a(lynx)

Question

I customized the vendor image in AOSP by modifying BoardConfigPartial.mk to generate a custom vendor image rather than using the prebuilt one. After successfully flashing the custom vendor image onto my device, it boots up fine but does not detect the SIM card.

Steps I Took:

1. Commented out the prebuilt vendor image line:

   # BOARD_PREBUILT_VENDORIMAGE := vendor/google_devices/lynx/proprietary/vendor.img
   

2. Added the following lines to enable vendor image generation:

   ENABLE_VENDOR_IMAGE := true
   BOARD_VENDORIMAGE_PARTITION_SIZE := 1073741824 # 1GB
   BOARD_VENDORIMAGE_FILE_SYSTEM_TYPE := ext4
   TARGET_COPY_OUT_VENDOR := vendor
   ALLOW_MISSING_DEPENDENCIES := true
   

3. Noticed that the initial custom vendor image was smaller, so I compared it with the prebuilt one and added missing files to the build rules.
4. Successfully generated a custom vendor image with all necessary files.

Issue:

Despite successful boot, the device does not detect the SIM card after flashing the custom vendor image.

Question:

What steps can I take to troubleshoot and resolve the SIM card detection issue with my custom AOSP vendor image?

Thanks in advance for any guidance!

The device will look like below

Answer 1

This means that you're missing vendor proprietary files which were part of the original vendor image, and are not part of yours custom build, in the case of SIM (that is modem) it could be libril.so / vendor-libril.so / rild etc.. naming can change.. Try to see what ril related naming files are in the original image when you flash it to the device, vs your custom vendor image. Also examine the logcat radio buffer to begin analyzing the issue with the modem.