1. TWRP is a replacement for the stock recovery it can do everything the stock recovery can do plus it can flash zips, recoveries and boot images. It can also back up and restore system and data. It can also be entered from about any state of the phone except it being bricked of course. There is no need to use safestrap or flashfire anymore. I recommend that you remove safestrap from the rom you are using as it will cause trouble, by removing I mean uninstall safestrap recovery from the system just dont simply delete the apk. Flashfire can be left if you want as it wont affect anything.



2. You can flash TW roms as well as CM and AOSP based roms. The roms dont have to state they are for DEV edition. You will want to avoid muniz_ri upgrade roms as they flash bootloaders. In most cases if trying to flash a rom with bootloaders they will not flash but as a safety precaution avoid roms that say they flash bootloaders with the rom. Other Variants Roms can be flashed on the Verizon S5 also known as the SM-G900V. The other variants will have different letters at the end like SM-G900F witch is an international variant or SM-G900T wich is the Tmobile variant. SM-G900A ATT variant: SM-G900M Canadian variant SM-G900P Sprint variant. There are many other there are some you cant flash like the SM-G900H as this variant has a different chipset there are a few chinese and korean ones as well but you dont come across them much and they usually have some weird numbers. Now most of the other variants roms will need a patch to get data and mms working I have a patch that will work on most. Many of these roms come with there own custom TW kernels or there stock TW kernel. You can either use their kernel or you can use the verizon TW kernel on their roms. Most CM and AOSP roms will come with a kernel. Now CM and AOSP roms need to have google apps flashed in addition to the rom. These are commonly referred to as GApps



3. You can flash custom kernel. also know as a boot.img. ASOP CM and Touchwiz All have different kernels and the proper kernel must be flashed for the type of rom. You can use other variants kernels on the Verizon S5. Most work fine but some do not. There are alot more custom kernels for CM and AOSP than Touchwiz. Just remember Touchwiz roms need Touchwiz kernels rather it be a stock TW kernel or a modded TW kernel. And Most AOSP and CM kernels are interchangeable but you cannot use a TW kernel on those two



4. With TWRP you can use and install roms that have aroma installers. These installers give you choices throughout the install of what you want.



5. There are a couple of Marshmallow Touchwiz Roms available for the internation S5 the SM-G900F. As of now these roms cannot be used on our phones because they require a Marshmallow bootloader and modem. You can not use other variants firmware on the Verizon S5. By firmware I mean Bootloaders, Modems Etc. There are Also 5.1.1 roms available from ATT and Tmobile. It is possible to flash these roms as they will still run on the 5.0 lollipop bootloader. You may have to use there stock 5.1.1 kernel or a modded TW 5.1.1 kernel to get them to work



6. Roms 5.1.1 and higher require a different root method. Stock kernels have checks in them to prevent root so the kernel has to be modded to allow root. The newer SuperSU zips have a check for this and if they detect the kernel has not been modded then they will install whats called systemless root and a modded kernel ram disk. I just wanted to make people are that certain apps dont work with systemless root. If the kernel is properly modded then the old root method can be flashed



7. If you flash a rom that is not rooted it is no big deal since you have a custom recovery simply reboot to recovery and flash A SuperSU root zip or install a different rom



8 I recommend everyone be on lollipop bootloaders and firmware. There is no need to stay on kitkat firmware since you can now unlock the bootloader. KitKat Roms will run on lollipop bootloaders but lollipop roms will not run on kitkat bootloaders.



9. Just because your bootloaders is unlocked does not mean you can not run a fully stock unrooted rom if you want to. A fully stock rom will run just fine with unlocked bootloader and custom recovery installed.



10. When running custom kernels and recoveries it is normal during boot to have message at the top of your phone telling you that your basically running a custom recovery. or boot.img