[Android Software/Hacking General [Developers Only]] WhiteNeo:
Just a quick update concerning my comment above. :)

I fixed the bootloop and most other stuff, but have one last problem.

Vold can perfectly mount sdcard1, but keeps failing on sdcard0, with the logcat output "Permission denied"

Has anyone of you ever had a similar problem? If yes, please help me. :)

I don't really want to go for a dirty solution like mounting via init.rc. But if I have to (and permissions and stuff will be fine afterwards), I will.

Thanks in advance for any useful information :)

(And sorry for asking this off-topic stuff :o )

EDIT: Attaching a logcat. :)

Line 1289: I/SystemServer( 726): Mount Service
Line 1291: D/MountService( 726): got storage path: /storage/sdcard0 description: Interner Speicher primary: true removable: false emulated: false mtpReserve: 0 allowMassStorage: false maxFileSize: 0
Line 1293: D/MountService( 726): addVolumeLocked() StorageVolume:
Line 1295: D/MountService( 726): mStorageId=0 mPath=/storage/sdcard0 mDescriptionId=17040836 mPrimary=true
Line 1297: D/MountService( 726): mRemovable=false mEmulated=false mMtpReserveSpace=0
Line 1299: D/MountService( 726): mAllowMassStorage=false mMaxFileSize=0 mOwner=null mUuid=null
Line 1301: D/MountService( 726): mUserLabel=null mState=null
Line 1303: D/MountService( 726): got storage path: /storage/sdcard1 description: SD-Karte primary: false removable: true emulated: false mtpReserve: 0 allowMassStorage: false maxFileSize: 0
Line 1305: D/MountService( 726): addVolumeLocked() StorageVolume:
Line 1307: D/MountService( 726): mStorageId=0 mPath=/storage/sdcard1 mDescriptionId=17040837 mPrimary=false
Line 1309: D/MountService( 726): mRemovable=true mEmulated=false mMtpReserveSpace=0 mAllowMassStorage=false
Line 1311: D/MountService( 726): mMaxFileSize=0 mOwner=null mUuid=null mUserLabel=null mState=null
Line 1313: D/MountService( 726): got storage path: /storage/usbdisk description: USB-Speicher primary: false removable: true emulated: false mtpReserve: 0 allowMassStorage: false maxFileSize: 0
Line 1315: D/MountService( 726): addVolumeLocked() StorageVolume:
Line 1317: D/MountService( 726): mStorageId=0 mPath=/storage/usbdisk mDescriptionId=17040838 mPrimary=false
Line 1319: D/MountService( 726): mRemovable=true mEmulated=false mMtpReserveSpace=0 mAllowMassStorage=false
Line 1321: D/MountService( 726): mMaxFileSize=0 mOwner=null mUuid=null mUserLabel=null mState=null
Line 1331: W/MountService( 726): Duplicate state transition (unmounted -> unmounted) for /storage/sdcard0
Line 1331: W/MountService( 726): Duplicate state transition (unmounted -> unmounted) for /storage/sdcard0
Line 1331: W/MountService( 726): Duplicate state transition (unmounted -> unmounted) for /storage/sdcard0
Line 1333: W/MountService( 726): Duplicate state transition (unmounted -> unmounted) for /storage/sdcard1
Line 1333: W/MountService( 726): Duplicate state transition (unmounted -> unmounted) for /storage/sdcard1
Line 1333: W/MountService( 726): Duplicate state transition (unmounted -> unmounted) for /storage/sdcard1
Line 1335: D/MountService( 726): volume state changed for /storage/usbdisk (unmounted -> removed)
Line 1335: D/MountService( 726): volume state changed for /storage/usbdisk (unmounted -> removed)
Line 1339: W/MountService( 726): getSecureContainerList() called when storage not mounted
Line 1339: W/MountService( 726): getSecureContainerList() called when storage not mounted
Line 1447: W/MountService( 726): getSecureContainerList() called when storage not mounted
Line 1447: W/MountService( 726): getSecureContainerList() called when storage not mounted
Line 1953: D/Vold ( 259): Volume sdcard0 state changing 1 (Idle-Unmounted) -> 3 (Checking)
Line 1959: D/MountService( 726): volume state changed for /storage/sdcard0 (unmounted -> checking)
Line 1959: D/MountService( 726): volume state changed for /storage/sdcard0 (unmounted -> checking)
Line 1961: D/MountService( 726): sendStorageIntent Intent { act=android.intent.action.MEDIA_CHECKING dat=file:///storage/sdcard0 flg=0x4000000 (has extras) } to UserHandle{-1}
[COLOR="Red"][B]Line 2005: E/Vold ( 259): /dev/block/vold/179:15 failed to mount via EXT4 (Permission denied)[/B][/COLOR]
Line 2007: E/Vold ( 259): Volume sdcard0 found no suitable devices for mounting :(
Line 2009: D/Vold ( 259): Volume sdcard0 state changing 3 (Checking) -> 1 (Idle-Unmounted)
Line 2013: D/MountService( 726): volume state changed for /storage/sdcard0 (checking -> unmounted)
Line 2013: D/MountService( 726): volume state changed for /storage/sdcard0 (checking -> unmounted)
Line 2015: I/PackageManager( 726): Updating external media status from unmounted to unmounted
Line 2015: I/PackageManager( 726): Updating external media status from unmounted to unmounted
Line 2017: D/MountService( 726): sendStorageIntent Intent { act=android.intent.action.MEDIA_UNMOUNTED dat=file:///storage/sdcard0 flg=0x4000000 (has extras) } to UserHandle{-1}
Line 2017: D/MountService( 726): sendStorageIntent Intent { act=android.intent.action.MEDIA_UNMOUNTED dat=file:///storage/sdcard0 flg=0x4000000 (has extras) } to UserHandle{-1}
Line 2019: E/VoldConnector( 726): NDC Command {5 volume mount /storage/sdcard0} took too long (879ms)
Line 2021: E/MountService( 726): Boot-time mount failed (-1)
Line 2021: E/MountService( 726): Boot-time mount failed (-1)
Line 2025: D/Vold ( 259): Volume sdcard1 state changing 1 (Idle-Unmounted) -> 3 (Checking)
Line 2029: D/MountService( 726): volume state changed for /storage/sdcard1 (unmounted -> checking)
Line 2029: D/MountService( 726): volume state changed for /storage/sdcard1 (unmounted -> checking)
Line 2031: D/MountService( 726): sendStorageIntent Intent { act=android.intent.action.MEDIA_CHECKING dat=file:///storage/sdcard1 flg=0x4000000 (has extras) } to UserHandle{-1}
Line 3051: D/Vold ( 259): Volume sdcard1 state changing 3 (Checking) -> 4 (Mounted)
Line 3053: D/MountService( 726): volume state changed for /storage/sdcard1 (checking -> mounted)
Line 3053: D/MountService( 726): volume state changed for /storage/sdcard1 (checking -> mounted)
Line 3055: D/MountService( 726): sendStorageIntent Intent { act=android.intent.action.MEDIA_MOUNTED dat=file:///storage/sdcard1 flg=0x4000000 (has extras) } to UserHandle{-1}
Line 3055: D/MountService( 726): sendStorageIntent Intent { act=android.intent.action.MEDIA_MOUNTED dat=file:///storage/sdcard1 flg=0x4000000 (has extras) } to UserHandle{-1}
Line 3057: E/VoldConnector( 726): NDC Command {6 volume mount /storage/sdcard1} took too long (1373ms)
Line 4307: I/ActivityManager( 726): Start proc com.android.externalstorage for broadcast com.android.externalstorage/.MountReceiver: pid=1524 uid=10008 gids={50008, 9997, 1028, 1015, 1023} abi=armeabi-v7a
Line 4377: D/MediaScannerReceiver( 838): action: android.intent.action.MEDIA_UNMOUNTED path: /storage/sdcard0
Line 5473: D/Vold ( 259): Volume sdcard0 state changing 2 (Pending) -> 1 (Idle-Unmounted)
Line 5481: D/Vold ( 259): Volume sdcard1 state changing 2 (Pending) -> 1 (Idle-Unmounted)