Jacoco Coverage Report issues

I am trying to define the location, where jacoco will create the coverage file for instrumentation tests running on real devices.

From the --debug run of the gradle task I see this log:

[DEBUG] [org.gradle.api.Task] DeviceConnector 'Nexus 5X - 6.0.1': installing /home/martin/workspace/lib/my-lib/build/outputs/apk/my-lib-debug-androidTest-unaligned.apk
[INFO] [org.gradle.api.Task] Starting 1 tests on Nexus 5X - 6.0.1
[INFO] [org.gradle.api.Task]  de.my.lib.utils.UtilsTest testMyTest[Nexus 5X - 6.0.1] [32mSUCCESS [0m
[DEBUG] [org.gradle.api.Task] DeviceConnector 'Nexus 5X - 6.0.1': fetching coverage data from /data/data/de.my.lib.test/coverage.ec
[DEBUG] [org.gradle.api.Task] DeviceConnector 'Nexus 5X - 6.0.1': uninstalling de.my.lib.test 13:46:14.538
[DEBUG] [org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter] Finished executing task ':my-lib:connectedDebugAndroidTest'

I tried 3 ways to define the location:

Using the <instrumentation> tag in the manifest file didn't change anything.

<?xml version="1.0" encoding="utf-8"?>
<manifest
    package="de.my.lib.test"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <instrumentation
        android:name="android.support.test.runner.AndroidJUnitRunner"
        xmlns:tools="http://schemas.android.com/tools"
        android:targetPackage="de.my.lib.test"
        tools:replace="android:targetPackage">
        <meta-data
            android:name="coverage"
            android:value="true" />
        <meta-data
            android:name="coverageFile"
            android:value="/sdcard/coverage.ec" />
    </instrumentation>
</manifest>

I tried it with gradle but the output was the same:

defaultConfig {
    // unimportant stuff
    testApplicationId "de.my.lib.test"

    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    testInstrumentationRunnerArgument('coverageFile', '/sdcard/coverage.ec')
}

And finally I tried it with adb command:

adb shell am instrument -w -e coverage true -e coverageFile /sdcard/coverage.ec de.my.lib.test/android.support.test.runner.AndroidJUnitRunner

But there I get 2 errors:

de.my.lib.utils.UtilsTest:. Could not find class: org.jacoco.agent.rt.internal_773e439.CoverageTransformer . Time: 0,072

OK (1 test)

Error: Failed to generate emma coverage.

I am completely lost here. Any ideas?

Background Why I need it to have it stored in another place: There is a bug with adb shell run-as command on some devices and Android version so I have devices in my test device farm which return 0% coverage because the file can't be pulled. So I need the file to be stored in a publicly available location.

from Jacoco Coverage Report issues