Galaxy Z Flip 4 - Black Screen Crashes and Knox Framework Errors

[Mr Polainas]

• Subject: Galaxy Z Flip 4 - Black Screen Crashes and Knox Framework Errors

  Device Information:

  • Model: Galaxy Z Flip 4
  • Software: One UI 6 (Android 14)
  • Build Info: adb shell getprop ro.build.version.release returns 14, adb shell getprop ro.build.id output available if needed.

  Issue Description:
  My Galaxy Z Flip 4 frequently experiences black screen crashes, making the phone unusable until I reboot it. The screen goes completely black during normal use, such as folding/unfolding the device or turning the screen on/off. System logs reveal persistent errors in the Knox framework, which I believe are contributing to this instability.

  Error Logs (Key Excerpts):

  • Primary Knox Error (EnterpriseDeviceManagerService):
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    2025-04-28 09:39:47.043 2303-2475 Enterprise...gerService system_server E isMdmAdminPresentInternal() : failed. java.lang.IllegalArgumentException: Unknown admin: ComponentInfo{...} at com.android.server.enterprise.EnterpriseDeviceManagerServiceImpl.findAdmin(EnterpriseDeviceManagerServiceImpl.java:1567)
  • Additional Knox Errors (VpnManagerService and MDM Provider):
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    2025-04-28 09:39:47.202 2303-3399 VpnManagerService system_server E Exception occurred while trying to get the getProxyInfoForUid for knoxvpn uid 10275 2025-04-28 09:39:46.805 2303-5864 KNOX_MDM_S...gsProvider system_server D isChangeAllowed() : name = ltc_highsoc_exceed_time

  Frequency and Context:
  These errors occur frequently during actions like turning the screen on/off, folding/unfolding the device, or launching apps. The black screen crashes often happen during these same actions, rendering the phone unusable until rebooted.

  Steps to Reproduce:

  1. Perform normal device actions like folding/unfolding the phone, turning the screen on/off, or launching apps.
  2. Observe black screen crashes and check Logcat for the errors above.

  Attempts to Resolve:

  • Performed a factory reset.
  • Cleared Knox app data (com.samsung.android.knox.containercore, com.samsung.android.knox.attestation, etc.).
  • Disabled and re-enabled Knox apps via ADB, then cleared their data again.
  • The errors and black screen crashes persist.

  Why the Screen Goes Black (Explanation):
  The black screen crashes seem to be caused by system instability tied to errors in the Knox framework. The EnterpriseDeviceManagerService error indicates that Knox is failing to handle certain system checks properly, likely due to a bug that leaves behind outdated data it can’t process. This error, along with the VpnManagerService issue related to Knox’s VPN functionality (knoxvpn), suggests that Knox is causing conflicts within the system. These conflicts might be overloading critical system services, leading to crashes that freeze the display and result in a black screen. The timing of the errors during actions like folding/unfolding or screen on/off points to Knox interfering with display or activity management processes, causing the system to fail and the screen to go black.

  Suggested Fix:
  The issue lies in Samsung’s Knox framework (com.samsung.android.knox.EnterpriseDeviceManager). There’s a bug that prevents Knox from clearing outdated system records, leading to repeated errors and system instability. I suggest releasing a firmware update to:

  • Fix EnterpriseDeviceManagerService to properly handle and clear outdated records.
  • Resolve VpnManagerService errors related to knoxvpn.
  • Address the system instability causing black screen crashes, making the phone usable again.

[JordanS]

Quite the in-depth report you have here, @Mr Polainas. We have had to move it out of our ideas and suggestions thread as it didn't quite fit there. 

For submitting error reports, it's advised to do so through the feedback section within the Samsung Members app. First, wait for the issue to occur, then once able, long press on the Samsung Members app > Error report > Select your phone and the relevant category > Add your extensive details > Down at the bottom, select Attach System Log Data > Send > Keep the screen awake and stay on the app until the logs have compiled for sending. 

Once our R&D team have analysed your report and logs, they will be in touch with their findings and a resolution. 

[Mr Polainas]

Hello Jordan, 

thanks for the reply but as I stated I have screen issues and i totally understand it should be made on the phone but sometimes phones do not work, there should be an app in pc we can connect the phone and send the report or maybe an online form to do that. Again not blaming just sharing my opinion thanks.

[Mr Polainas]

I tried to send my report several times in the Members app, and all I got was, 'We need pictures to replicate the error.' I responded that it's very hard to get pictures if the screen is black. Anyways, it seems they just don't care about the issue. It's evident it's a crash in the system UI. My last option is to reload the full firmware. Do you know if it is possible? I tried with Smart Switch, but I can't see the option anywhere.