[OnePlus 8 Pro  ROMs, Kernels, Recoveries, & Other ] tbalden:
Thanks... here are something I found in the logs compared, especially in logcat.

On Op8 "OpIris" is a few lines in the logs. On op8pro (120hz stuff) it's this:

Crash logs (not present in op8)

05-08 18:57:12.570 1633 1633 D OpIrisWhiteListManager: init
05-08 18:57:12.571 1633 1633 D OpIrisWhiteListParser: parseXml sdr2hdr text: com.tencent.qqlive type: 267-3-1 appType :1
05-08 18:57:12.571 1633 1633 D OpIrisWhiteListParser: parseXml sdr2hdr text: com.qiyi.video type: 267-3-1 appType :1
05-08 18:57:12.571 1633 1633 D OpIrisWhiteListParser: parseXml sdr2hdr text: com.youku.phone type: 267-3-1 appType :1
05-08 18:57:12.571 1633 1633 D OpIrisWhiteListParser: parseXml sdr2hdr text: com.oneplus.gallery type: 267-3-1 appType :1
05-08 18:57:12.571 1633 1633 D OpIrisWhiteListParser: parseXml sdr2hdr text: com.tencent.qqsports type: 267-3-1 appType :1
....
05-08 18:57:12.576 1633 1633 E ActivityManager: Caused by: java.util.NoSuchElementException
05-08 18:57:12.576 1633 1633 E ActivityManager: at android.os.HwBinder.getService(Native Method)
05-08 18:57:12.576 1633 1633 E ActivityManager: at android.os.HwBinder.getService(HwBinder.java:83)
05-08 18:57:12.576 1633 1633 E ActivityManager: at sis.sis.zta.zta.zta.sis.getService(Unknown Source:2)
05-08 18:57:12.576 1633 1633 E ActivityManager: at sis.sis.zta.zta.zta.sis.getService(Unknown Source:2)
05-08 18:57:12.576 1633 1633 E ActivityManager: at com.oneplus.android.server.iris.ssp.zta(Unknown Source:6)
05-08 18:57:12.576 1633 1633 E ActivityManager: at com.oneplus.android.server.iris.sis.init(Unknown Source:18)
05-08 18:57:12.576 1633 1633 E ActivityManager: at com.oneplus.android.server.iris.sis.<init>(Unknown Source:129)
05-08 18:57:12.576 1633 1633 E ActivityManager: at com.oneplus.android.server.iris.OpIrisService.<init>(Unknown Source:40)
05-08 18:57:12.576 1633 1633 E ActivityManager: at com.oneplus.android.server.context.OneplusContextStubImpl.<init>(Unknown Source:1699)

Then:

--------- beginning of crash
05-08 18:57:12.583 1633 1633 E AndroidRuntime: *** FATAL EXCEPTION IN SYSTEM PROCESS: main
05-08 18:57:12.583 1633 1633 E AndroidRuntime: java.lang.RuntimeException: Failed to start service com.android.server.am.ActivityManagerService$Life
05-08 18:57:12.583 1633 1633 E AndroidRuntime: at com.android.server.SystemServiceManager.startService(SystemServiceManager.java:131)
05-08 18:57:12.583 1633 1633 E AndroidRuntime: at com.android.server.SystemServiceManager.startService(SystemServiceManager.java:116)
05-08 18:57:12.583 1633 1633 E AndroidRuntime: at com.android.server.am.ActivityManagerService$Lifecycle.startService(ActivityManagerService.
05-08 18:57:12.583 1633 1633 E AndroidRuntime: at com.android.server.SystemServer.startBootstrapServices(SystemServer.java:688)
05-08 18:57:12.583 1633 1633 E AndroidRuntime: at com.android.server.SystemServer.run(SystemServer.java:538)
05-08 18:57:12.583 1633 1633 E AndroidRuntime: at com.android.server.SystemServer.main(SystemServer.java:377)
05-08 18:57:12.583 1633 1633 E AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)
05-08 18:57:12.583 1633 1633 E AndroidRuntime: at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:516)
05-08 18:57:12.583 1633 1633 E AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:928)
05-08 18:57:12.583 1633 1633 E AndroidRuntime: Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'void com.oneplus.andro
05-08 18:57:12.583 1633 1633 E AndroidRuntime: at com.android.server.am.ActivityManagerService.start(ActivityManagerService.java:2895)
05-08 18:57:12.583 1633 1633 E AndroidRuntime: at com.android.server.am.ActivityManagerService.access$1000(ActivityManagerService.java:507)
05-08 18:57:12.583 1633 1633 E AndroidRuntime: at com.android.server.am.ActivityManagerService$Lifecycle.onStart(ActivityManagerService.java:
05-08 18:57:12.583 1633 1633 E AndroidRuntime: at com.android.server.SystemServiceManager.startService(SystemServiceManager.java:129)
05-08 18:57:12.583 1633 1633 E AndroidRuntime: ... 8 more

This will stop starting of system in the end..

No idea what's missing, but it's HW related , so probably some driver missing

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