[Xposed Framework Modules] _jis_:
Great, this version work as it should. MTP settings is persistent across USB (dis)connecting and rebooting too. Next production version should clean the error log from debug messages :)

12-20 14:06:56.483 I/Xposed ( 236): -----------------
12-20 14:06:56.483 I/Xposed ( 236): Starting Xposed version 78, compiled for SDK 23
12-20 14:06:56.483 I/Xposed ( 236): Device: Nexus 7 (asus), Android version 6.0 (SDK 23)
12-20 14:06:56.483 I/Xposed ( 236): ROM: MRA58V
12-20 14:06:56.483 I/Xposed ( 236): Build fingerprint: google/razor/flo:6.0/MRA58V/2324235:user/release-keys
12-20 14:06:56.483 I/Xposed ( 236): Platform: armeabi-v7a, 32-bit binary, system server: yes
12-20 14:06:56.483 I/Xposed ( 236): SELinux enabled: yes, enforcing: yes
12-20 14:06:56.491 I/Xposed ( 236): -----------------
12-20 14:06:56.492 I/Xposed ( 236): Added Xposed (/system/framework/XposedBridge.jar) to CLASSPATH
12-20 14:06:57.053 I/Xposed ( 236): Detected ART runtime
12-20 14:06:57.113 I/Xposed ( 236): Found Xposed class de/robv/android/xposed/XposedBridge, now initializing
12-20 14:06:57.554 I/Xposed ( 236): Loading modules from /data/app/com.ceco.marshmallow.gravitybox-2/base.apk
12-20 14:06:57.880 I/Xposed ( 236): Loading class com.ceco.marshmallow.gravitybox.GravityBox
12-20 14:06:57.912 I/Xposed ( 236): GB:Hardware: flo
12-20 14:06:57.912 I/Xposed ( 236): GB:Product: razor
12-20 14:06:57.912 I/Xposed ( 236): GB:Device manufacturer: asus
12-20 14:06:57.912 I/Xposed ( 236): GB:Device brand: google
12-20 14:06:57.912 I/Xposed ( 236): GB:Device model: Nexus 7
12-20 14:06:57.924 I/Xposed ( 236): GB:Device type: tablet
12-20 14:06:57.924 I/Xposed ( 236): GB:Is MTK device: false
12-20 14:06:57.924 I/Xposed ( 236): GB:Is Xperia device: false
12-20 14:06:57.924 I/Xposed ( 236): GB:Is Moto XT device: false
12-20 14:06:57.927 I/Xposed ( 236): GB:Has Lenovo custom UI: false
12-20 14:06:57.931 I/Xposed ( 236): GB:Has telephony support: false
12-20 14:06:57.931 I/Xposed ( 236): GB:Has Gemini support: false
12-20 14:06:57.931 I/Xposed ( 236): GB:Android SDK: 23
12-20 14:06:57.931 I/Xposed ( 236): GB:Android Release: 6.0
12-20 14:06:57.931 I/Xposed ( 236): GB:ROM: MRA58V
12-20 14:06:58.006 I/Xposed ( 236): Loading modules from /data/app/ma.wanam.youtubeadaway-2/base.apk
12-20 14:06:58.025 I/Xposed ( 236): Loading class ma.wanam.youtubeadaway.Xposed
12-20 14:06:58.027 I/Xposed ( 236): Loading modules from /data/app/com.germainz.activityforcenewtask-1/base.apk
12-20 14:06:58.049 I/Xposed ( 236): Loading class com.germainz.activityforcenewtask.XposedMod
12-20 14:06:58.066 I/Xposed ( 236): Loading modules from /data/app/rayyan.black.fem.ind.runner-2/base.apk
12-20 14:06:58.145 I/Xposed ( 236): Loading class rayyan.black.fem.ind.runner.UUSBF
12-20 14:06:58.192 I/Xposed ( 236): Loading modules from /data/app/de.robv.android.xposed.mods.appsettings-1/base.apk
12-20 14:06:58.223 I/Xposed ( 236): Loading class de.robv.android.xposed.mods.appsettings.XposedMod
12-20 14:06:58.247 I/Xposed ( 236): Loading modules from /data/app/com.germainz.crappalinks-1/base.apk
12-20 14:06:58.273 I/Xposed ( 236): Loading class com.germainz.crappalinks.CrappaLinks
12-20 14:06:58.285 I/Xposed ( 236): Loading modules from /data/app/de.theknut.xposedgelsettings-1/base.apk
12-20 14:06:58.403 I/Xposed ( 236): Loading class de.theknut.xposedgelsettings.hooks.ResourceReplacements
12-20 14:06:58.432 I/Xposed ( 236): Loading class de.theknut.xposedgelsettings.hooks.GELSettings
12-20 14:06:58.440 I/Xposed ( 236): Loading modules from /data/app/com.p1ngu1n.playstorechangelog-1/base.apk
12-20 14:06:58.459 I/Xposed ( 236): Loading class com.p1ngu1n.playstorechangelog.PlayStoreChangelog
12-20 14:07:22.682 I/Xposed ( 807): UUSBF: mContext.>>>mContext>android.app.ContextImpl@6f62a15
12-20 14:07:24.421 I/Xposed ( 977): UUSBF: com.android.settings.deviceinfo.UsbBackend is not available
12-20 14:07:29.759 I/Xposed ( 807): UUSBF: : onReceive: Intent { act=android.hardware.usb.action.USB_STATE flg=0x30000010 (has extras) }
12-20 14:07:39.674 I/Xposed ( 2444): UUSBF: com.android.settings.deviceinfo.UsbBackend is not available
12-20 14:08:12.342 I/Xposed ( 4569): UUSBF: com.android.settings.deviceinfo.UsbBackend is not available
12-20 14:09:39.645 I/Xposed ( 807): UUSBF: : onReceive: Intent { act=android.hardware.usb.action.USB_STATE flg=0x30000010 (has extras) }
12-20 14:09:39.646 I/Xposed ( 807): UUSBF: mService>com.android.server.usb.UsbService@2fa5069
12-20 14:09:39.651 I/Xposed ( 807): UUSBF: Key>0true
12-20 14:09:39.730 I/Xposed ( 807): UUSBF: : onReceive: Intent { act=android.hardware.usb.action.USB_STATE flg=0x30000010 (has extras) }
12-20 14:09:39.730 I/Xposed ( 807): UUSBF: mService>com.android.server.usb.UsbService@2fa5069
12-20 14:09:39.730 I/Xposed ( 807): UUSBF: Key>0false
12-20 14:09:46.331 I/Xposed ( 5585): UUSBF: com.android.settings.deviceinfo.UsbBackend is not available
12-20 14:09:50.992 I/Xposed ( 5585): UUSBF: getCurrentFunction>>>>>com.android.settings.deviceinfo.UsbModeChooserActivity@78d90c3
12-20 14:09:50.996 I/Xposed ( 5585): UUSBF: getCurrentFunction value=0
12-20 14:09:50.996 I/Xposed ( 5585): UUSBF: map value=0
12-20 14:09:53.246 I/Xposed ( 5585): UUSBF: setCurrentFunction=com.android.settings.deviceinfo.UsbModeChooserActivity@78d90c3
12-20 14:09:53.246 I/Xposed ( 5585): UUSBF: value=2
12-20 14:09:53.246 I/Xposed ( 5585): UUSBF: writeConfiguration>>>>>com.android.settings.deviceinfo.UsbModeChooserActivity@78d90c3
12-20 14:09:53.246 I/Xposed ( 5585): UUSBF: writeConfiguration>>>>>2
12-20 14:09:53.247 I/Xposed ( 807): UUSBF: : onReceive: Intent { act=android.hardware.usb.action.USB_STATE flg=0x30000010 (has extras) }
12-20 14:09:53.247 I/Xposed ( 807): UUSBF: mService>com.android.server.usb.UsbService@2fa5069
12-20 14:09:53.247 I/Xposed ( 807): UUSBF: Key>0false
12-20 14:09:53.456 I/Xposed ( 807): UUSBF: : onReceive: Intent { act=android.hardware.usb.action.USB_STATE flg=0x30000010 (has extras) }
12-20 14:09:53.456 I/Xposed ( 807): UUSBF: mService>com.android.server.usb.UsbService@2fa5069
12-20 14:09:53.456 I/Xposed ( 807): UUSBF: Key>2false
12-20 14:09:53.540 I/Xposed ( 807): UUSBF: : onReceive: Intent { act=android.hardware.usb.action.USB_STATE flg=0x30000010 (has extras) }
12-20 14:09:53.540 I/Xposed ( 807): UUSBF: mService>com.android.server.usb.UsbService@2fa5069
12-20 14:09:53.540 I/Xposed ( 807): UUSBF: Key>2false
12-20 14:10:15.035 I/Xposed ( 807): UUSBF: : onReceive: Intent { act=android.hardware.usb.action.USB_STATE flg=0x30000010 (has extras) }
12-20 14:10:20.127 I/Xposed ( 807): UUSBF: : onReceive: Intent { act=android.hardware.usb.action.USB_STATE flg=0x30000010 (has extras) }
12-20 14:10:20.127 I/Xposed ( 807): UUSBF: mService>com.android.server.usb.UsbService@2fa5069
12-20 14:10:20.127 I/Xposed ( 807): UUSBF: Key>2true
12-20 14:10:20.150 I/Xposed ( 807): UUSBF: : onReceive: Intent { act=android.hardware.usb.action.USB_STATE flg=0x30000010 (has extras) }
12-20 14:10:20.150 I/Xposed ( 807): UUSBF: mService>com.android.server.usb.UsbService@2fa5069
12-20 14:10:20.151 I/Xposed ( 807): UUSBF: Key>2false
12-20 14:10:20.325 I/Xposed ( 807): UUSBF: : onReceive: Intent { act=android.hardware.usb.action.USB_STATE flg=0x30000010 (has extras) }
12-20 14:10:20.325 I/Xposed ( 807): UUSBF: mService>com.android.server.usb.UsbService@2fa5069
12-20 14:10:20.326 I/Xposed ( 807): UUSBF: Key>2false
12-20 14:10:20.412 I/Xposed ( 807): UUSBF: : onReceive: Intent { act=android.hardware.usb.action.USB_STATE flg=0x30000010 (has extras) }
12-20 14:10:20.412 I/Xposed ( 807): UUSBF: mService>com.android.server.usb.UsbService@2fa5069
12-20 14:10:20.412 I/Xposed ( 807): UUSBF: Key>2false
12-20 14:10:38.637 I/Xposed ( 5585): UUSBF: getCurrentFunction>>>>>com.android.settings.deviceinfo.UsbModeChooserActivity@7c75ba0
12-20 14:10:38.637 I/Xposed ( 5585): UUSBF: getCurrentFunction value=2
12-20 14:10:38.638 I/Xposed ( 5585): UUSBF: map value=1
12-20 14:10:45.076 I/Xposed ( 807): UUSBF: : onReceive: Intent { act=android.hardware.usb.action.USB_STATE flg=0x30000010 (has extras) }