Hello.
I'm trying to do an OS update on my TC57 running Android 8.1 GMS.
Current build number is "01-21-18.00-OG-U00-STD".
The intended update should go to LGU09 using the file HE_DELTA_UPDATE_01-21-18.00-OG-U09.zip and by submitting this MX command from within our MDM agent using MDM toolkit API:

The TC57 reboots and seems to start the OS update.
But the SO update does not succeed. Instead, after some seconds the device just shows a green Android image, subtitled with "Error" and then reboots with the unchanged OS release.
In the recovery logs I see these entries:
[ 0.368214] -- Path /sdcard/MdmAgentOsUpdate.zip.
[ 0.391123] __bionic_open_tzdata: couldn't find any tzdata when looking for GMT!
[ 0.391176] __bionic_open_tzdata: couldn't find any tzdata when looking for posixrules!
[ 0.391259] FUSE exfat 1.3.0
[ 0.391267] ERROR: failed to open '/dev/block/mmcblk1p1': No such file or directory.
[ 0.391412] mount.exfat: failed to open '/dev/block/mmcblk1p1': No such file or directory
[ 1.387242]
[ 1.387250] -- Install /sdcard/MdmAgentOsUpdate.zip ...
[ 1.401719]
[ 1.401726] -- open /sdcard/MdmAgentOsUpdate.zip code : -11 ...
[ 1.418175] E:Can't OpenArchive/sdcard/MdmAgentOsUpdate.zip : I/O error
[ 6.462291] I:buildID from build.prop=01-21-18.00-OG-U00-STD
[ 6.464616] I:Checking for block map files to delete
[ 6.464629] I:No block map file to delete
[ 6.464663] I:in copy_logs
[ 6.464669] I:
I tried different ZIP file locations and file names - according to the hints on https://techdocs.zebra.com/emdk-for-android/7-6/mx/powermgr/.
I also tried different update binary files (HE_DELTA_UPDATE_01-21-18.00-OG-U03.zip, HE_DELTA_UPDATE_01-21-18.00-OG_TO_01-23-18.U00-OG.zip)
The OS update always fails with the same error.
On other models (like TC77 and TC20) the OS update is working flawless, but not on my TC57 unit.
What's the reason for the reported zip file I/O error? What does error "-11" indicate?