[Galaxy S 4 Developer Discussion [Developers-Only]] Fenny:
I got a preliminary merge done with framework/apk files from the i9505:

I am building now to test...

Here is a more complete listing of the functions that were involved. There ARE some missing. I got a bit anxious around 85% of the way through and stopped documenting.. silly me.

Functions needing merge:

SecMms/smali/com/android/mms/transaction/HttpUtils.smali
.method protected static httpConnection(Landroid/content/Context;JLjava/lang/String;[BIZLjava/lang/String;ILandroid/net/http/AndroidHttpClient;Lorg/apache/http/HttpRequest;)[B

SecMms/smali/com/android/mms/transaction/PushReceiver$ReceivePushTask.smali
.method private isDataAvailable()Z

./SecMms/smali/com/android/mms/transaction/RetrieveAckTransaction.smali
.method private isNetworkAvailable()Z

./SecMms/smali/com/android/mms/transaction/RetryScheduler.smali
.method private constructor <init>(Landroid/content/Context;)V
.method private isConnected()Z

./SecMms/smali/com/android/mms/transaction/Transaction.smali
.method private ensureRouteToHost(Ljava/lang/String;Lcom/android/mms/transaction/TransactionSettings;)V

./SecMms/smali/com/android/mms/transaction/TransactionService.smali
.method private isNetworkAvailable()Z
.method protected beginMmsConnectivity()I
.method public onDestroy()V

./SecMms/smali/com/android/mms/ui/ComposeMessageFragment.smali
.method public confirmSendMessageIfNeeded()V
.method public onResume()V
.method public onOptionsItemSelected(Landroid/view/MenuItem;)Z
.method networkWarningDialogAndSend(Z)V

./SecContacts/smali/com/android/contacts/detail/ContactDetailFragment$ViewAdapter$4.smali
.method public onClick(Landroid/view/View;)V

./SecContacts/smali/com/android/contacts/detail/ContactDetailFragment.smali
.method public onCreate(Landroid/os/Bundle;)V
.method public onPause()V
.method public onResume()V

./SecContacts/smali/com/android/contacts/list/ContactEntryListFragment.smali
.method public onCreate(Landroid/os/Bundle;)V
.method public onResume()V
.method public onPause()V

./SecContacts/smali/com/android/contacts/list/ContactTileListFragment.smali
.method public onCreate(Landroid/os/Bundle;)V
.method public onResume()V
.method public onPause()V

./SecContacts/smali/com/android/contacts/quickcontact/QuickContactListFragment.smali
.method static synthetic access$800(Lcom/android/contacts/quickcontact/QuickContactListFragment;)Lcom/sec/android/app/contacts/util/ImsLowSignalHelper;
.locals 1
.parameter "x0"

.prologue
.line 78
iget-object v0, p0, Lcom/android/contacts/quickcontact/QuickContactListFragment;->mImsLowSignalHelper:Lcom/sec/android/app/contacts/util/ImsLowSignalHelper;

return-object v0
.end method
.method public onResume()V
.method public onPause()V

./SecContacts/smali/com/android/contacts/quickcontact/QuickContactListFragment$2.smali
.method public onClick(Landroid/view/View;)V

./SecContacts/smali/com/sec/android/app/contacts/list/ContactListSweepActionListener.smali
.method public onSweepActionFired(II)V

./SecContacts/smali/com/sec/android/app/dialertab/calllog/CallDetailActivity.smali
.method protected onCreate(Landroid/os/Bundle;)V
.method protected onPause()V

./SecContacts/smali/com/sec/android/app/dialertab/calllog/CallLogFragment.smali
.method public callSelectedEntry()V
.method public onCreate(Landroid/os/Bundle;)V
.method public onPause()V
.method public onResume()V
.method public setSweepActionEnabled(Z)V

./SecContacts/smali/com/sec/android/app/dialertab/dialpad/DialpadFragment.smali
.method private placeCall_result(Ljava/lang/String;)V
.method private setupAddtionalButtons(Landroid/view/View;)V
.method public callVisualVoiceMail()V
.method public callVoicemail()V
.method public dialButtonPressed()V
.method public onCreate(Landroid/os/Bundle;)V
.method public onPause()V
.method public onResume()V

./SecContacts/smali/com/sec/android/app/dialertab/widget/DialtactsListSweepActionListener.smali
.method public onSweepActionFired(II)V

./SecPhone/smali/com/android/phone/CallCard.smali
.method private updateDisplayForConference(Lcom/android/internal/telephony/Call;)V
.method updateMySoundBtn(Lcom/android/internal/telephony/Call$State;)V

./SecPhone/smali/com/android/phone/CallController.smali
.method private placeCallInternal(Landroid/content/Intent;)Lcom/android/phone/Constants$CallStatusCode;

./SecPhone/smali/com/android/phone/CallFeaturesSetting.smali
.field private mWifiCallSwitchPreference:Landroid/preference/Preference;
.method private registerRegReceiver(Z)V
.method private updateEtcPreference()V
.method protected initGeneralSetting(Z)V
.method protected initVideoSetting(Z)V
.method public onCreate(Landroid/os/Bundle;)V
.method public onPause()V
.method public onResume()V

./SecPhone/smali/com/android/phone/GsmUmtsAdditionalCallOptions.smali
.method public onFinished(Landroid/preference/Preference;Z)V
.method public onPause()V
.method public onResume()V

./SecPhone/smali/com/android/phone/GsmUmtsAdditionalCallOptions$3.smali
.method public onReceive(Landroid/content/Context;Landroid/content/Intent;)V

./SecPhone/smali/com/android/phone/IccNetworkDepersonalizationPanel$2.smali
Replace file, and subfiles.

./SecPhone/smali/com/android/phone/InCallMenu.smali
.method protected prepareOptionsMenu(Landroid/view/Menu;)Z

./SecPhone/smali/com/android/phone/InCallTouchUi.smali
.method private updateInCallIcons(Lcom/android/phone/InCallControlState;)V

./SecSettings/smali/com/android/settings/deviceinfo/Status.smali
.method private registerRegReceiver(Z)V
.method public onPause()V
.method protected onResume()V

./SecSettings/smali/com/android/settings/wifi/WifiSettings.smali
.method private updateConnectionState(Landroid/net/NetworkInfo$DetailedState;)V

./SecSettings/smali/com/android/settings/SecuritySettings.smali
.method private createPreferenceHierarchy()Landroid/preference/PreferenceScreen;

./services.jar.out/smali/com/android/server/WifiService.smali
.method constructor <init>(Landroid/content/Context;)V
.method private setNotificationVisible(ZIZI)V

Side Note:
./SecMms/smali/com/android/mms/ui/ComposeMessageFragment.smali
.method public static isWhiteTheme()Z

./SecMms/smali/com/android/mms/MmsConfig.smali
+ const-string v10, "http://wap.samsungmobile.com/uaprof/SGH-M919.xml"
- const-string v10, "http://wap.samsungmobile.com/uaprof/GT-I9505.xml"

Will post back with results soon, I am building my own custom kernel from the i9505 source, because it seems that the current (latest) stock kernel binaries have some sort of anti suid patch.