[Epic 4G Android Development] Firon:
These are all the files that need to live in /system/app before the updater will work. There's also some files in /system/framework it checks for, but if you removed those, you're probably in trouble ;)

/system/app/AccountAndSyncSettings.odex
/system/app/AlarmClock.odex
/system/app/ApplicationsProvider.odex
/system/app/BluetoothOPP.apk
/system/app/BluetoothOPP.odex
/system/app/BluetoothServices.odex
/system/app/BluetoothTestMode.odex
/system/app/Brightness.odex
/system/app/Browser.apk
/system/app/Browser.odex
/system/app/BuddiesNow.odex
/system/app/CallSetting.odex
/system/app/Camera.apk
/system/app/Camera.odex
/system/app/CameraFirmware.odex
/system/app/CertInstaller.odex
/system/app/Contacts.apk
/system/app/Contacts.odex
/system/app/ContactsProvider.apk
/system/app/ContactsProvider.odex
/system/app/DataCreate.odex
/system/app/DeviceManagement.apk
/system/app/DeviceManagement.odex
/system/app/DialerTabActivity.odex
/system/app/Divx.odex
/system/app/Dlna.apk
/system/app/Dlna.odex
/system/app/DownloadProvider.odex
/system/app/DrmProvider.odex
/system/app/DrmUA.odex
/system/app/Dun.odex
/system/app/Email.apk
/system/app/Email.odex
/system/app/EnhancedGoogleSearchProvider.apk
/system/app/FactoryTest.odex
/system/app/FlashPlugin.apk
/system/app/FlashPlugin.odex
/system/app/FlashSVGPlayer.apk
/system/app/FlashSVGPlayer.odex
/system/app/Gallery3D.apk
/system/app/Gallery3D.odex
/system/app/GlobalSearch.odex
/system/app/Gmail.apk
/system/app/GmailProvider.apk
/system/app/GoogleApps.apk
/system/app/GoogleCheckin.apk
/system/app/GoogleContactsSyncAdapter.apk
/system/app/GooglePartnerSetup.apk
/system/app/GoogleSearch.odex
/system/app/GoogleSettingsProvider.apk
/system/app/GoogleSubscribedFeedsProvider.apk
/system/app/GpsSetup.odex
/system/app/HTMLViewer.odex
/system/app/HiddenMenu.odex
/system/app/InputEventApp.odex
/system/app/JobManager.odex
/system/app/KeyBoardSlideUpCounter.odex
/system/app/Keytracer.odex
/system/app/LatinImeTutorial.apk
/system/app/Launcher.apk
/system/app/Launcher.odex
/system/app/LiveWallpapers.odex
/system/app/LiveWallpapersPicker.odex
/system/app/LogsProvider.odex
/system/app/Maps.apk
/system/app/MarketUpdater.apk
/system/app/MediaProvider.odex
/system/app/Memo.odex
/system/app/Mms.apk
/system/app/Mms.odex
/system/app/MobileAP.apk
/system/app/MobileAP.odex
/system/app/Music.apk
/system/app/Music.odex
/system/app/MyFiles.apk
/system/app/MyFiles.odex
/system/app/NetworkLocation.apk
/system/app/OtaProvisioningService.odex
/system/app/PackageInstaller.odex
/system/app/Phone.apk
/system/app/Phone.odex
/system/app/PhoneCrashNotifier.odex
/system/app/PhoneErrService.apk
/system/app/PhoneErrService.odex
/system/app/PhoneInfo.odex
/system/app/PicoTts.odex
/system/app/SamsungWidget_CalendarClock.odex
/system/app/SamsungWidget_FeedAndUpdate.odex
/system/app/SamsungWidget_ProgramMonitor.odex
/system/app/SamsungWidget_StockClock.odex
/system/app/SamsungWidget_WeatherClock.odex
/system/app/SelectiveReset.odex
/system/app/Settings.apk
/system/app/Settings.odex
/system/app/SettingsProvider.apk
/system/app/SettingsProvider.odex
/system/app/SetupWizard.apk
/system/app/SisoDrmProvider.odex
/system/app/SnsAccount.odex
/system/app/SnsProvider.odex
/system/app/SoundRecorder.odex
/system/app/SprintTV.apk
/system/app/SprintZone.apk
/system/app/Street.apk
/system/app/Swype.apk
/system/app/TATLiveWallpapersDandelion.odex
/system/app/TATLiveWallpapersLuminescence.odex
/system/app/TATLiveWallpapersOceanWave.odex
/system/app/Talk.apk
/system/app/TalkProvider.apk
/system/app/TelephonyProvider.odex
/system/app/TouchWiz30Launcher.odex
/system/app/TouchWizCalculator.odex
/system/app/TouchWizCalendar.odex
/system/app/TouchWizCalendarProvider.odex
/system/app/TtsService.odex
/system/app/UserDictionaryProvider.odex
/system/app/Vending.apk
/system/app/VideoPlayer.apk
/system/app/VideoPlayer.odex
/system/app/VoiceDialer.odex
/system/app/VoiceSearchWithKeyboard.apk
/system/app/VpnServices.odex
/system/app/WiMAXLineTest.apk
/system/app/WlanTest.odex
/system/app/amazonmp3.apk
/system/app/audioTuning.odex
/system/app/gtalkservice.apk
/system/app/lcdtest.odex
/system/app/serviceModeApp.odex
/system/app/shutdown.odex