[Xposed Framework Modules] Dysternaut:
Okay, I set out to try and do this to the NFC APK found on my LG G4 with stock rom.

However, there are only LgNfc.apk and NfcSettings.apk to be found on this rom. Neither of these have a classes.dex in them.

Saw in an earlier post that this means that I need to deox the files. So I downloaded the tool Universal Deodex V5 and succesfully pilled the framework from the phone via the tool, and afterwards deoxed the two apk files with this output:

Welcome!
Deodexing LgNfc.apk
Compression=5
API=19
EXTENSION=apk
1 file(s) copied.
1 file(s) copied.
Disassembling odex file..
Exception in thread "main" org.jf.util.ExceptionWithContext: LgNfc.odex is not an apk, dex file or odex file.
at org.jf.dexlib2.DexFileFactory.loadDexFile(DexFileFactory.java:111)
at org.jf.dexlib2.DexFileFactory.loadDexFile(DexFileFactory.java:54)
at org.jf.baksmali.main.main(main.java:252)

Creating classes.dex file..

UNEXPECTED TOP-LEVEL EXCEPTION:
java.lang.RuntimeException: Cannot find file or directory "out/"
at org.jf.smali.main.main(main.java:174)
1 file(s) moved.

7-Zip (A) 4.65 Copyright (c) 1999-2009 Igor Pavlov 2009-02-03

Processing archive: LgNfc.apk

Extracting AndroidManifest.xml
Extracting assets\star.png
Extracting res\drawable-hdpi-v4\ic_menu_cancel_holo_dark.png
Extracting res\drawable-hdpi-v4\nfc.png
Extracting res\drawable-hdpi-v4\stat_sys_nfc.png
Extracting res\drawable-mdpi-v4\back.png
Extracting res\drawable-mdpi-v4\p2p_bg.png
Extracting res\drawable-xxhdpi-v4\icon.png
Extracting res\drawable-xxhdpi-v4\tap_again.png
Extracting res\drawable-xxxhdpi-v4\android_beam.png
Extracting res\drawable-xxxhdpi-v4\stat_sys_lge_nfc_card.png
Extracting res\drawable-xxxhdpi-v4\stat_sys_lge_nfc_forum.png
Extracting res\layout\cardemu_item.xml
Extracting res\layout\cardemu_payment_item.xml
Extracting res\layout\cardemu_resolver.xml
Extracting res\layout\popupconfirm.xml
Extracting res\layout\screenshot.xml
Extracting res\layout\tapagain.xml
Extracting res\raw\end.ogg
Extracting res\raw\error.ogg
Extracting res\raw\start.ogg
Extracting res\xml\additions.xml
Extracting res\xml\token_sync.xml
Extracting resources.arsc
Extracting META-INF\MANIFEST.MF
Extracting META-INF\CERT.SF
Extracting META-INF\CERT.RSA

Everything is Ok

Files: 27
Size: 1033300
Compressed: 1020799
Repacking deodexed apk..

7-Zip (A) 4.65 Copyright (c) 1999-2009 Igor Pavlov 2009-02-03
Scanning

Creating archive LgNfc.apk

Compressing AndroidManifest.xml
Compressing assets\star.png
Compressing META-INF\CERT.RSA
Compressing META-INF\CERT.SF
Compressing META-INF\MANIFEST.MF
Compressing resources.arsc
Compressing res\drawable-hdpi-v4\ic_menu_cancel_holo_dark.png
Compressing res\drawable-hdpi-v4\nfc.png
Compressing res\drawable-hdpi-v4\stat_sys_nfc.png
Compressing res\drawable-mdpi-v4\back.png
Compressing res\drawable-mdpi-v4\p2p_bg.png
Compressing res\drawable-xxhdpi-v4\icon.png
Compressing res\drawable-xxhdpi-v4\tap_again.png
Compressing res\drawable-xxxhdpi-v4\android_beam.png
Compressing res\drawable-xxxhdpi-v4\stat_sys_lge_nfc_card.png
Compressing res\drawable-xxxhdpi-v4\stat_sys_lge_nfc_forum.png
Compressing res\layout\cardemu_item.xml
Compressing res\layout\cardemu_payment_item.xml
Compressing res\layout\cardemu_resolver.xml
Compressing res\layout\popupconfirm.xml
Compressing res\layout\screenshot.xml
Compressing res\layout\tapagain.xml
Compressing res\raw\end.ogg
Compressing res\raw\error.ogg
Compressing res\raw\start.ogg
Compressing res\xml\additions.xml
Compressing res\xml\token_sync.xml

Everything is Ok
1 file(s) copied.
DEODEXING COMPLETE!

================COMPLETED DEODEXING===============
===================DEODEXED 2 of 2===============
Done checking 50%
Done checking 100%
FAILED : LgNfc.apk
FAILED : NfcSettings.apk

Writing Log to file..
DONE WRITING.
=======DEODEXING PROCESS COMPLETE=====

So it seems the tool won't accept the odex file from the phone, and I am now at a loss. If anyone can point me in a direction to go from here, please do let me know!

EDIT: Okay, got a bit further. Seems that tool doesn't support Lollipop.

So I found this guide:

http://www.apktopwebsite.com/how-to-deodex-your-lollipop-rom.html

Followed it, and deoxed my whole ROM. However, only the NfcSettings.apk gets deoxed, LgNfc.apk for some unknown reason, does not. The tool doesn't even acknowledge it! And the NfcSettings. apk does not seem to have the NfcService.smali, or something similar, as referenced in the guide in the thread. I guess I will keep pocking around, but suggestions, again, are welcome.

EDIT AGAIN:

Okay, finally deoxed everything with this awesome tool:

http://xdaforums.com/galaxy-s5/general/tool-deodex-tool-android-l-t2972025

Followed the guide on the LgNfc.apk, and now it works with screen off! Thanks a bunch to everyone in this thread for the guides and such. :D

Final file is attached. Note that this is for screen off. Also, the original file is from stock rom version V10d-EUR-XX and it's a H815 NEU variant, in case it is relevant.