I just purchased a few refurbished Samsung (S3, S4, S5) devices from Gazelle for a testing lab I'm organizing. The product listings for each said they had Android 4.2, 4.3, and 4.4 respectively. However, when they arrived and booted up, they all appear to have 4.4.2 installed. Factory reset seems to only reset to version 4.4.2. Is there a way to (without rooting) revert the devices back to previous versions of Android?
Yes. There's a very easy way using Odin.
First, download odin from above link and also download whatever android version firmware you want from Sammobile, also download samsung drivers. Then extract the odin archive.
Now, enable USB Debugging mode from developer options on your phone
Backup everything from phones. Data will be erased.
Now run odin and click on PDA button and point it to firmware file downloaded in earlier step.
Switch off your device completely. After that, turn your device on in download or Odin mode. This can be done by simultaneously holding the power button+volume down+home button on your phone. You should now be in download mode (it should say
Downloading.... Do not turn off Target!).
Connect phone to pc using usb now. Once connected, the ID:COM section in Odin should turn to light blue. This means that the device has been connected and is ready for flashing. If it doesn't show any response, you may need to reinstall drivers.
Make sure "Auto Reboot" and "F.Reset Time" are enabled and disable every other option.
Startin odin and wait a while, it may take sometime. Once done, it should say
Finally boot the phone, first boot may take a while so wait atleast for 20mins by watch.
Perform these steps separately for every phone one by one.
Good luck, and hope it helps :)
Unfortunately, this might not be possible or cheap. version 4.4 usually comes with secured bootloader, which is not downgradable by PC.
But give it a try, worst thing would be that you'll permanently disable KNOX on the s5. As an attempt to downgrade FW is considered a security risk because of allowing old FW's exploits. the s3 and s4 don't have the knox trigger AFAIK.
It's not for sure, so you definitely should try, but before you begin, Note down your current FW version exactly if you don't and flashing of old FW will fail, you'll need to flash as close version to the old one as possible, because all parts of FW will get overwritten except for the bootloader and the phone won't probably even boot , or will work with issues.
But don't worry, if that happened, flashing back the previous, or maybe newer version of the FW will restore everything, except probably for the KNOX on the s5. The important version info is under Settings-About device-BUILD NUMBER
Dumping the original FW would be too much hassle and would require root, so a better option is, if you'll need to go back to original FW, to search for it using only second part of the version-string, e.g. on mine it's XXXXXX.N910FXXU1BOC5 so I would search N910FXXU1BOC5
as for the second part of the first sentence, a more costly way of doing this is to give those phones to a company offering "unbricking of hard brick phones".
I mean you give them your working phones and tell them to flesh them with older fW. Maybe even too old, if they won't have exact version. then you still can go up.
Unbricking of hard bricks is done by removing the memory chip and flashing it outside of the phone, the culprit then won't be able to tell what's happening during the surgery and so an downgrade should after all be possible.