diff --git a/mobile/android/geckoview/build.gradle b/mobile/android/geckoview/build.gradle
index ae4390794107..8501591028cf 100644
--- a/mobile/android/geckoview/build.gradle
+++ b/mobile/android/geckoview/build.gradle
@@ -69,8 +69,6 @@ android {
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
 
         buildConfigField 'String', "GRE_MILESTONE", "\"${mozconfig.substs.GRE_MILESTONE}\""
-        // This should really come from the included binaries, but that's not easy.
-        buildConfigField 'String', "MOZ_APP_ABI", mozconfig.substs['COMPILE_ENVIRONMENT'] ? "\"${ mozconfig.substs.TARGET_XPCOM_ABI}\"" : '"arm-eabi-gcc3"';
         buildConfigField 'String', "MOZ_APP_BASENAME", "\"${mozconfig.substs.MOZ_APP_BASENAME}\"";
 
         // For the benefit of future archaeologists:
@@ -92,8 +90,6 @@ android {
         buildConfigField 'String', "USER_AGENT_GECKOVIEW_MOBILE", "\"Mozilla/5.0 (Android \" + android.os.Build.VERSION.RELEASE + \"; Mobile; rv: ${mozconfig.substs.MOZ_APP_VERSION}) Gecko/${mozconfig.substs.MOZ_APP_VERSION} GeckoView/${mozconfig.substs.MOZ_APP_VERSION}\"";
         buildConfigField 'String', "USER_AGENT_GECKOVIEW_TABLET", "\"Mozilla/5.0 (Android \" + android.os.Build.VERSION.RELEASE + \"; Tablet; rv: ${mozconfig.substs.MOZ_APP_VERSION}) Gecko/${mozconfig.substs.MOZ_APP_VERSION} GeckoView/${mozconfig.substs.MOZ_APP_VERSION}\"";
 
-        buildConfigField 'String', "ANDROID_CPU_ARCH", "\"${mozconfig.substs.ANDROID_CPU_ARCH}\"";
-
         buildConfigField 'int', 'MIN_SDK_VERSION', mozconfig.substs.MOZ_ANDROID_MIN_SDK_VERSION;
 
         // Is the underlying compiled C/C++ code compiled with --enable-debug?
diff --git a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/ContentDelegateTest.kt b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/ContentDelegateTest.kt
index f3629515fb6f..27410be56b2c 100644
--- a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/ContentDelegateTest.kt
+++ b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/ContentDelegateTest.kt
@@ -84,7 +84,7 @@ class ContentDelegateTest : BaseSessionTest() {
         assumeThat(sessionRule.env.isMultiprocess, equalTo(true))
         // Cannot test x86 debug builds due to Gecko's "ah_crap_handler"
         // that waits for debugger to attach during a SIGSEGV.
-        assumeThat(sessionRule.env.isDebugBuild && sessionRule.env.cpuArch == "x86",
+        assumeThat(sessionRule.env.isDebugBuild && sessionRule.env.isX86,
                    equalTo(false))
 
         mainSession.loadUri(CONTENT_CRASH_URL)
@@ -115,7 +115,7 @@ class ContentDelegateTest : BaseSessionTest() {
         assumeThat(sessionRule.env.isMultiprocess, equalTo(true))
         // Cannot test x86 debug builds due to Gecko's "ah_crap_handler"
         // that waits for debugger to attach during a SIGSEGV.
-        assumeThat(sessionRule.env.isDebugBuild && sessionRule.env.cpuArch == "x86",
+        assumeThat(sessionRule.env.isDebugBuild && sessionRule.env.isX86,
                    equalTo(false))
 
         mainSession.delegateUntilTestEnd(object : Callbacks.ContentDelegate {
@@ -141,7 +141,7 @@ class ContentDelegateTest : BaseSessionTest() {
         assumeThat(sessionRule.env.isMultiprocess, equalTo(true))
         // Cannot test x86 debug builds due to Gecko's "ah_crap_handler"
         // that waits for debugger to attach during a SIGSEGV.
-        assumeThat(sessionRule.env.isDebugBuild && sessionRule.env.cpuArch == "x86",
+        assumeThat(sessionRule.env.isDebugBuild && sessionRule.env.isX86,
                    equalTo(false))
 
         // XXX we need to make sure all sessions in a given content process receive onCrash().
diff --git a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/GeckoSessionTestRuleTest.kt b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/GeckoSessionTestRuleTest.kt
index 79b5c923700b..3d931c73eb77 100644
--- a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/GeckoSessionTestRuleTest.kt
+++ b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/GeckoSessionTestRuleTest.kt
@@ -1661,7 +1661,7 @@ class GeckoSessionTestRuleTest : BaseSessionTest(noErrorCollector = true) {
         assumeThat(sessionRule.env.isMultiprocess, equalTo(true))
         // Cannot test x86 debug builds due to Gecko's "ah_crap_handler"
         // that waits for debugger to attach during a SIGSEGV.
-        assumeThat(sessionRule.env.isDebugBuild && sessionRule.env.cpuArch == "x86",
+        assumeThat(sessionRule.env.isDebugBuild && sessionRule.env.isX86,
                    equalTo(false))
 
         mainSession.loadUri(CONTENT_CRASH_URL)
@@ -1678,7 +1678,7 @@ class GeckoSessionTestRuleTest : BaseSessionTest(noErrorCollector = true) {
         assumeThat(sessionRule.env.shouldShutdownOnCrash(), equalTo(false))
         // Cannot test x86 debug builds due to Gecko's "ah_crap_handler"
         // that waits for debugger to attach during a SIGSEGV.
-        assumeThat(sessionRule.env.isDebugBuild && sessionRule.env.cpuArch == "x86",
+        assumeThat(sessionRule.env.isDebugBuild && sessionRule.env.isX86,
                    equalTo(false))
 
         sessionRule.session.loadUri(CONTENT_CRASH_URL)
diff --git a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/crash/CrashTest.kt b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/crash/CrashTest.kt
index e240f16bbd1f..3f4461154f8e 100644
--- a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/crash/CrashTest.kt
+++ b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/crash/CrashTest.kt
@@ -37,7 +37,7 @@ class CrashTest {
 
     fun getTimeoutMillis(): Long {
         val env = Environment()
-        if ("x86" == env.cpuArch) {
+        if (env.isX86) {
             return if (env.isEmulator)
                 CrashTest.DEFAULT_X86_EMULATOR_TIMEOUT_MILLIS
             else
diff --git a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/util/Environment.java b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/util/Environment.java
index 9a00c7d4794d..bb7729fef039 100644
--- a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/util/Environment.java
+++ b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/util/Environment.java
@@ -56,12 +56,19 @@ public class Environment {
         return BuildConfig.DEBUG_BUILD;
     }
 
-    public String getCPUArch() {
-        return BuildConfig.ANDROID_CPU_ARCH;
+    public boolean isX86() {
+        final String abi;
+        if (Build.VERSION.SDK_INT >= 21) {
+            abi = Build.SUPPORTED_ABIS[0];
+        } else {
+            abi = Build.CPU_ABI;
+        }
+
+        return abi.startsWith("x86");
     }
 
     public long getScaledTimeoutMillis() {
-        if ("x86".equals(getCPUArch())) {
+        if (isX86()) {
             return isEmulator() ? DEFAULT_X86_EMULATOR_TIMEOUT_MILLIS
                                 : DEFAULT_X86_DEVICE_TIMEOUT_MILLIS;
         }
diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/mozglue/GeckoLoader.java b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/mozglue/GeckoLoader.java
index 2178dea8ef72..3fbb083fc4f4 100644
--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/mozglue/GeckoLoader.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/mozglue/GeckoLoader.java
@@ -8,6 +8,7 @@ package org.mozilla.gecko.mozglue;
 import org.mozilla.gecko.GeckoAppShell;
 import org.mozilla.gecko.annotation.JNITarget;
 import org.mozilla.gecko.annotation.RobocopTarget;
+import org.mozilla.gecko.util.HardwareUtils;
 import org.mozilla.geckoview.BuildConfig;
 
 import android.content.Context;
@@ -314,8 +315,10 @@ public final class GeckoLoader {
         message.append(lib);
 
         // These might differ. If so, we know why the library won't load!
-        message.append(": ABI: " + BuildConfig.MOZ_APP_ABI + ", " + getCPUABI());
+        HardwareUtils.init(context);
+        message.append(": ABI: " + HardwareUtils.getLibrariesABI() + ", " + getCPUABI());
         message.append(": Data: " + context.getApplicationInfo().dataDir);
+
         try {
             final boolean appLibExists = new File("/data/app-lib/" + androidPackageName + "/lib" + lib + ".so").exists();
             final boolean dataDataExists = new File("/data/data/" + androidPackageName + "/lib/lib" + lib + ".so").exists();
diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/HardwareUtils.java b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/HardwareUtils.java
index 9848f680e0a7..c04e6c47dff2 100644
--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/HardwareUtils.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/HardwareUtils.java
@@ -15,6 +15,11 @@ import android.util.Log;
 import org.mozilla.gecko.SysInfo;
 import org.mozilla.geckoview.BuildConfig;
 
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+
 public final class HardwareUtils {
     private static final String LOGTAG = "GeckoHardwareUtils";
 
@@ -30,13 +35,14 @@ public final class HardwareUtils {
     private static volatile boolean sIsSmallTablet;
     private static volatile boolean sIsTelevision;
 
+    private static volatile File sLibDir;
+    private static volatile int sMachineType = -1;
+
     private HardwareUtils() {
     }
 
     public static void init(Context context) {
         if (sInited) {
-            // This is unavoidable, given that HardwareUtils is called from background services.
-            Log.d(LOGTAG, "HardwareUtils already inited.");
             return;
         }
 
@@ -53,6 +59,7 @@ public final class HardwareUtils {
             }
         }
 
+        sLibDir = new File(context.getApplicationInfo().dataDir, "lib");
         sInited = true;
     }
 
@@ -120,6 +127,63 @@ public final class HardwareUtils {
         return getPreferredAbi();
     }
 
+    private static final int ELF_MACHINE_UNKNOWN = 0;
+    private static final int ELF_MACHINE_X86 = 0x03;
+    private static final int ELF_MACHINE_X86_64 = 0x3e;
+    private static final int ELF_MACHINE_ARM = 0x28;
+    private static final int ELF_MACHINE_AARCH64 = 0xb7;
+
+    private static int readElfMachineType(final File file) {
+        try (final FileInputStream is = new FileInputStream(file)) {
+            final byte[] buf = new byte[17];
+            int count = 0;
+            while (count != buf.length) {
+                count += is.read(buf, count, buf.length - count);
+            }
+
+            return buf[16];
+        } catch (FileNotFoundException e) {
+            Log.w(LOGTAG, String.format("Failed to open %s", file.getAbsolutePath()));
+            return ELF_MACHINE_UNKNOWN;
+        } catch (IOException e) {
+            Log.w(LOGTAG, "Failed to read library", e);
+            return ELF_MACHINE_UNKNOWN;
+        }
+    }
+
+    private static String machineTypeToString(int machineType) {
+        switch (machineType) {
+            case ELF_MACHINE_X86:
+                return "x86";
+            case ELF_MACHINE_X86_64:
+                return "x86_64";
+            case ELF_MACHINE_ARM:
+                return "arm";
+            case ELF_MACHINE_AARCH64:
+                return "aarch64";
+            case ELF_MACHINE_UNKNOWN:
+            default:
+                return "unknown";
+        }
+    }
+
+    private static void initMachineType() {
+        if (sMachineType >= 0) {
+            return;
+        }
+
+        sMachineType = readElfMachineType(new File(sLibDir, System.mapLibraryName("mozglue")));
+    }
+
+    /**
+     * @return The ABI of the libraries installed for this app.
+     */
+    public static String getLibrariesABI() {
+        initMachineType();
+
+        return machineTypeToString(sMachineType);
+    }
+
     /**
      * @return false if the current system is not supported (e.g. APK/system ABI mismatch).
      */
@@ -130,14 +194,16 @@ public final class HardwareUtils {
             return false;
         }
 
+        initMachineType();
+
         // See http://developer.android.com/ndk/guides/abis.html
         final boolean isSystemX86 = isX86System();
         final boolean isSystemARM = !isSystemX86 && isARMSystem();
         final boolean isSystemARM64 = isARM64System();
 
-        boolean isAppARM = BuildConfig.ANDROID_CPU_ARCH.startsWith("armeabi-v7a");
-        boolean isAppARM64 = BuildConfig.ANDROID_CPU_ARCH.startsWith("arm64-v8a");
-        boolean isAppX86 = BuildConfig.ANDROID_CPU_ARCH.startsWith("x86");
+        final boolean isAppARM = sMachineType == ELF_MACHINE_ARM;
+        final boolean isAppARM64 = sMachineType == ELF_MACHINE_AARCH64;
+        final boolean isAppX86 = sMachineType == ELF_MACHINE_X86;
 
         // Only reject known incompatible ABIs. Better safe than sorry.
         if ((isSystemX86 && isAppARM) || (isSystemARM && isAppX86)) {
@@ -150,7 +216,7 @@ public final class HardwareUtils {
         }
 
         Log.w(LOGTAG, "Unknown app/system ABI combination: " +
-                      BuildConfig.MOZ_APP_ABI + " / " + getRealAbi());
+                      machineTypeToString(sMachineType) + " / " + getRealAbi());
         return true;
     }
 }