diff --git a/cmds/pm/src/com/android/commands/pm/Pm.java b/cmds/pm/src/com/android/commands/pm/Pm.java
index b7f1ff9..d6c17ae 100644
--- a/cmds/pm/src/com/android/commands/pm/Pm.java
+++ b/cmds/pm/src/com/android/commands/pm/Pm.java
@@ -998,8 +998,8 @@
 
         final InstallSessionParams params = new InstallSessionParams();
         params.installFlags = PackageManager.INSTALL_ALL_USERS;
-        params.mode = InstallSessionParams.MODE_FULL_INSTALL;
-        params.progressMax = -1;
+        params.setModeFullInstall();
+        params.setProgressMax(-1);
 
         String opt;
         while ((opt = nextOption()) != null) {
@@ -1021,10 +1021,11 @@
             } else if (opt.equals("-d")) {
                 params.installFlags |= PackageManager.INSTALL_ALLOW_DOWNGRADE;
             } else if (opt.equals("-p")) {
-                params.mode = InstallSessionParams.MODE_INHERIT_EXISTING;
+                params.setModeInheritExisting();
             } else if (opt.equals("-S")) {
-                params.deltaSize = Long.parseLong(nextOptionData());
-                params.progressMax = (int) params.deltaSize;
+                final long deltaSize = Long.parseLong(nextOptionData());
+                params.setDeltaSize(deltaSize);
+                params.setProgressMax((int) params.deltaSize);
             } else if (opt.equals("--abi")) {
                 params.abiOverride = checkAbiArgument(nextOptionData());
             } else {
diff --git a/services/core/java/com/android/server/pm/PackageInstallerService.java b/services/core/java/com/android/server/pm/PackageInstallerService.java
index 190e87c..db915e2 100644
--- a/services/core/java/com/android/server/pm/PackageInstallerService.java
+++ b/services/core/java/com/android/server/pm/PackageInstallerService.java
@@ -76,6 +76,10 @@
     @GuardedBy("mSessions")
     private final SparseArray<PackageInstallerSession> mSessions = new SparseArray<>();
 
+    /** Historical sessions kept around for debugging purposes */
+    @GuardedBy("mSessions")
+    private final SparseArray<PackageInstallerSession> mHistoricalSessions = new SparseArray<>();
+
     private RemoteCallbackList<IPackageInstallerObserver> mObservers = new RemoteCallbackList<>();
 
     private static final FilenameFilter sStageFilter = new FilenameFilter() {
@@ -344,18 +348,29 @@
     }
 
     void dump(IndentingPrintWriter pw) {
-        pw.println("Active install sessions:");
-        pw.increaseIndent();
         synchronized (mSessions) {
-            final int N = mSessions.size();
+            pw.println("Active install sessions:");
+            pw.increaseIndent();
+            int N = mSessions.size();
             for (int i = 0; i < N; i++) {
                 final PackageInstallerSession session = mSessions.valueAt(i);
                 session.dump(pw);
                 pw.println();
             }
+            pw.println();
+            pw.decreaseIndent();
+
+            pw.println("Historical install sessions:");
+            pw.increaseIndent();
+            N = mHistoricalSessions.size();
+            for (int i = 0; i < N; i++) {
+                final PackageInstallerSession session = mHistoricalSessions.valueAt(i);
+                session.dump(pw);
+                pw.println();
+            }
+            pw.println();
+            pw.decreaseIndent();
         }
-        pw.println();
-        pw.decreaseIndent();
     }
 
     class Callback {
@@ -367,6 +382,7 @@
             notifySessionFinished(session.sessionId, success);
             synchronized (mSessions) {
                 mSessions.remove(session.sessionId);
+                mHistoricalSessions.put(session.sessionId, session);
             }
             writeSessionsAsync();
         }
diff --git a/services/core/java/com/android/server/pm/PackageInstallerSession.java b/services/core/java/com/android/server/pm/PackageInstallerSession.java
index 31d9704..0e6a3f0 100644
--- a/services/core/java/com/android/server/pm/PackageInstallerSession.java
+++ b/services/core/java/com/android/server/pm/PackageInstallerSession.java
@@ -65,6 +65,7 @@
 
 public class PackageInstallerSession extends IPackageInstallerSession.Stub {
     private static final String TAG = "PackageInstaller";
+    private static final boolean LOGD = true;
 
     // TODO: enforce INSTALL_ALLOW_TEST
     // TODO: enforce INSTALL_ALLOW_DOWNGRADE
@@ -435,35 +436,25 @@
      */
     private void spliceExistingFilesIntoStage() throws PackageManagerException {
         final ApplicationInfo app = mPm.getApplicationInfo(mPackageName, 0, userId);
-        final File existingDir = new File(app.getBaseCodePath());
 
-        try {
-            linkTreeIgnoringExisting(existingDir, sessionStageDir);
-        } catch (ErrnoException e) {
-            throw new PackageManagerException(INSTALL_FAILED_INTERNAL_ERROR,
-                    "Failed to splice into stage");
-        }
-    }
+        int n = 0;
+        final File[] oldFiles = new File(app.getCodePath()).listFiles();
+        if (!ArrayUtils.isEmpty(oldFiles)) {
+            for (File oldFile : oldFiles) {
+                if (!PackageParser.isApkFile(oldFile)) continue;
 
-    /**
-     * Recursively hard link all files from source directory tree to target.
-     * When a file already exists in the target tree, it leaves that file
-     * intact.
-     */
-    private void linkTreeIgnoringExisting(File sourceDir, File targetDir) throws ErrnoException {
-        final File[] sourceContents = sourceDir.listFiles();
-        if (ArrayUtils.isEmpty(sourceContents)) return;
-
-        for (File sourceFile : sourceContents) {
-            final File targetFile = new File(targetDir, sourceFile.getName());
-
-            if (sourceFile.isDirectory()) {
-                targetFile.mkdir();
-                linkTreeIgnoringExisting(sourceFile, targetFile);
-            } else {
-                Libcore.os.link(sourceFile.getAbsolutePath(), targetFile.getAbsolutePath());
+                final File newFile = new File(sessionStageDir, oldFile.getName());
+                try {
+                    Os.link(oldFile.getAbsolutePath(), newFile.getAbsolutePath());
+                    n++;
+                } catch (ErrnoException e) {
+                    throw new PackageManagerException(INSTALL_FAILED_INTERNAL_ERROR,
+                            "Failed to splice into stage", e);
+                }
             }
         }
+
+        if (LOGD) Slog.d(TAG, "Spliced " + n + " existing APKs into stage");
     }
 
     @Override
diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java
index 0ad3a68..727cff0 100644
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -10026,9 +10026,6 @@
             }
         }
 
-        // Nuke any cached code
-        deleteCodeCacheDirsLI(pkgName);
-
         boolean sysPkg = (isSystemApp(oldPackage));
         if (sysPkg) {
             replaceSystemPackageLI(oldPackage, pkg, parseFlags, scanMode,
@@ -10066,6 +10063,7 @@
             deletedPkg = false;
         } else {
             // Successfully deleted the old package. Now proceed with re-installation
+            deleteCodeCacheDirsLI(pkgName);
             try {
                 final PackageParser.Package newPackage = scanPackageLI(pkg, parseFlags,
                         scanMode | SCAN_UPDATE_TIME, System.currentTimeMillis(), user, abiOverride);
@@ -10177,6 +10175,8 @@
         }
 
         // Successfully disabled the old package. Now proceed with re-installation
+        deleteCodeCacheDirsLI(packageName);
+
         res.returnCode = PackageManager.INSTALL_SUCCEEDED;
         pkg.applicationInfo.flags |= ApplicationInfo.FLAG_UPDATED_SYSTEM_APP;