Is it possible to clone a Phone then flash image on other phones?

This solution answers the question from a process perspective and details as relevant to your device have been linked (please do double check the version before downloading from links). Clarifications provided by you in our chat have been factored in. In short, it is as specific I can get to be without having the device and running through all the steps. Had two Samsung devices earlier and am quite familiar with most steps mentioned here (only CF auto root is new to me)

1. 50 phones is a tidy number and it may be possible that these have different version updates and maybe different modem versions. Select the latest one, make sure you are it works per your needs and let's call it "mother mobile".




2. From Sammobile site, download the stock ROM (which is on the mother mobile) . This will be your master copy to revert to stock if required. Store on laptop. Will come in handy when things go wrong and need to revert to stock.




3. There would be bloatware you would want to remove. Instead of uninstall, first freeze them using Titanium Pro and load your apps. If RAM and performance meet your needs, it is better to leave those apps frozen - never know if you would need them in future. If you decide to uninstall Titanium would do.




4. For unlocking bootloader if required (googling led me to understand that not required to unlock) please check with your carrier. They are carrier specific restrictions at times.




5. Download latest version of Odin, along with drivers corresponding to your Windows version and install on your laptop to connect to mobile. How to use is made clear on the website.




6. Rooting. Odin is undoubtedly best option for Samsung devices. Period. Odin with CF autoroot works with your device. This step by step tutorial explains how-to. I strongly suggest NOT even consider trying numerous one click apps available on play store, unless you are willing to experiment (Kingroot,Framaroot are among popular methods which may or may not work with your device). I recall reading that the stagefright vulnerability fix does not permit these exploits to be used (don't recall where I read that)

(Rooting and flashing TWRP) OR (flashing TWRP/custom recovery) triggers Knox rendering warranty void. That is how Samsung works (Does rooting (but no custom roms) trigger knox's void warranty). Flashing a custom ROM would also trigger Knox. There are workarounds mostly involving apps(of the one click variety), that use exploits and may or not work and hence not recommending them. If warranty not being void is important to you, please experiment and decide. Odin method is safe but trips Knox once you flash custom recovery

7. Custom Recovery. IMO, TWRP is the best in terms of it being easiest to use and also reliability. Download TWRP from the official website. One of many tutorials on net show how to root and flash TWRP




8. Download SuperSU latest version from official website




9. Now, you are all set for unlocking bootloader, rooting and flashing TWRP on your mother mobile. Once you are done, double check if rooted fully using apps like Root Checker. Configure mother mobile in terms of freezing unwanted apps, installing apps you need, setting up the user interface the way you want, launchers etc. Take two backups. First backup would be a complete back up or image This is ONLY to backup your mother mobile. Second back up or image would be WITHOUT EFS, and would be used for flashing on rest of devices. As already pointed out in another answer, EFS is device specific and flashing complete backup like the first back up discussed, on to any other device would almost certainly result in losing IMEI and emphatically not recommended (Tip: while backing up do not enable MD5 check option, it vastly increases imaging time without adding much value)




10. Now for rooting and flashing TWRP on other devices. Follow the same method as for mother mobile. Flashing TWRP through Odin is safest bet.




11. Now, coming to imaging on other devices. Copy the second image file (without EFS) on an ext SD or internal storage as you prefer and install image using TWRP. You could even take help from one or two of the bright, dependable end users and get done quickly. Typically a 3 gig image can be flashed in about 6 minutes, so two of you can get the job of populating images done in about 3 hours

Now, you know your end users better, but you are running the risk of end users if knowledgeable or plain curious to exploit root capabilities. But transferring the image from mother mobile in totality, including settings, app configurations, permissions etc. Quick complete imaging Vs warranty is the decision node.

Other alternative is to only root and set up each device individually and keep warranty intact, but of course end users are root empowered and if they mess around and trigger Knox, you can decide next steps.Educating them would help in keeping warranty intact and makes your job easier if they default. Guess this option is not what you are looking for

All the best.....