[General Questions and Answers] tanguero8:
I. INTRO AND SUMMARY: I decided to experiment with rooting on this phone, which was lying unused. I was successful, using KingoRoot but from a PC (the Android .apk version did not work for me). Below are the details.

II. NOTE ON MODEL: The "BLu Life One" nomenclature does not identify a specific phone since there were several branded with this name, sometimes but not always including extensions to the name like "XL." This guide is for the phone that, under Settings > About Device gives the following information: Model BLU LIFE ONE; Processor Qualcomm Technologies, Inc MSM8916; Android Version 5.0.2 (I had done an OTA update from 4.4.4 at some earlier point); Kernel Version 3.10.49; Build Number LRX22G release-keys; Custom Build Version BLU_X010Q_V11_L_GENERIC 20-01-2016 16:15. This phone is described at gsmarena dot com / blu_life_one_(2015)-6930 dot php with pictures, if you need to make sure.

III. PROCEDURE I FOLLOWED:

PART A: On Android Phone

1. Do a factory reset of the phone (after saving anything you may want from the phone beforehand to a different device, of course). Settings > Backup & reset > Factory data reset.

2a. Normally, I would do one more OTA update to get the latest Android version (if there was one) before rooting via Settings > About Device > Wireless Update. However, this crashed consistently and silently. My guess is that BLU changed their update server and the older models can no longer communicate with them, and the OTA update attempt fails (not very gracefully).

2b. When doing the initial setup of the phone coming out of reset, do NOT setup your WiFi yet (otherwise it will automatically try an OTA update and be in an endless loop trying to do so, owing to the problem mentioned above, and your phone will never initialize). Just choose your language and skip all other steps like WiFi, Google account login or setup, etc.

3. Once you have successfully initialized your phone in a clean state, then turn on WiFi and connect to a reliable network.

4. Become a developer on your Android (Settings > About device > Touch "Build Number" 7 times). Turn on USB Debugging (Settings > Developer options > USB Debugging).

5. Go to Settings > Display > Sleep and change to "30 minutes" or "Never" (you can change it back later, but I found the root process would suspend if the phone entered sleep).

6. Open the Play Store, set up your Google Account and download the app Root Checker (Joey Krim version), recommended by KingoRoot to verify that the rooting was successful. You may want to create a separate Google account for this purpose, otherwise if you connect to your primary one, it will attempt to sync your email, calendar, and all sorts of other stuff to your phone from your Google account, which you may not want at this point. Or you can try to disable all sync and all automatic App update from your Google account and Play Store as early in the process as it will let you.

PART B: On PC

** NOTE: You may want to read the section below IV. PROTECTING YOUR PC before doing this part! **

7. Connect your Android to your PC via the USB cable. It may try to download various drivers, some of which may be successful and others not, but don't worry if some driver installations appear to fail--Kingoroot apparently has its own ADB drivers that it installs during the early part of the rooting process.

8. On your PC, go to kingoapp.com (avoid downloading from other sites), and click on the "Download for Windows" link to download kingoroot.exe on your PC (I earlier tried the "Download for Android" link to sideload the KingoRoot.apk file, but this version stalled at 90% and did not work--the Windows version is stated as being more reliable and this turned out to be true for me).

9. Run kingoapp.exe on your PC with your phone connected, and let it install. Uncheck the box "Install Recommended App" when it appears and allow it to run. (The mysterious "Recommended App" turns out to be a sponsored "SuperBattery" App that's pretty useless. If you accidentally allow it to install, you get the option to uninstall it later.)

10. Accept installation of the Kingo Link App over the USB. Google "Play Protect" will try at least twice to warn you about the danger of allowing this, but if you want to root, you need to accept it.

11. The program will prompt you to enable USB Debug mode if you didn't already do it, then will install an ADB driver (which Windows Plug and Play was unable to install successfully in my case). You will then get a prompt on the phone to accept USB connection from the computer with signature specified. Check the box "Always Allow from this Computer" and allow.

12. Finally, the screen "BLU LIFE ONE / Root your Android. Make it more interesting!" screen will appear on the computer with a ROOT button. This means that the drivers installed properly and the KingoRoot PC program is communicating properly with the phone. Press the ROOT button, after unchecking the box "Install recommended app."

13. At various points, Google will ask to "check device activity for security problems, and prevent or warn about potential harm. / Learn more in the Google Settings App," which I always declined.

14. At various points, the phone screen will turn white and then return to the home screen. Finally, the computer should show "ROOT SUCCEED / Would you make a donation to support us?" You can close the PC program at this point.

PART C: On Android Phone

15. Reboot the phone (NOT a Factory Reset, just a simple Reboot). I found the Google Play would not work without this additional reboot.

16. Run the previously downloaded Root Checker App. A prompt from KingoRoot's SuperUser app will appear, asking you if you want to allow Root access to the Root Checker app, to which, of course, you must say "Yes." It should confirm that you have root access.

17. Do NOT uninstall the KingoRoot SuperUser App, otherwise you will lose root access. (It is possible to replace it with others like SuperSU, but that must be done and run FIRST, before uninstalling KingoRoot's SuperUser. I did not bother with replacing KingoRoot's SuperUser with another.)

IV. PROTECTING YOUR PC

Since I'm wary of installing software on my PC from sources that are by definition hacking sources, I took the following steps to protect my PC and it's data. You may wish to do the same, even though I have not read reports of KingoRoot, if downloaded from it's official site, containing Malware or covertly installed Adware. It IS suspicious, however, that the ADB driver installed by KingoRoot advertises itself as "Name: Google, Inc., Publisher: Finger Power Technology Co., Ltd." Clearly naming the driver "Google, Inc." is a way to reassure people who see the name "Google, Inc." on the screen without realizing that it's not in the "Publisher" field--one wonders why they would bother with this deception if there weren't an ulterior motive behind it.

1. I used an old netbook PC for the rooting, with no important data on it. I did NOT use my primary PC with my important data.

2. I ran the program under a non-administrative username. Of course, I had to provide an administrator password at two points, but at least I knew each time that administrative access was being requested.

3. I uninstalled the KingoRoot program from the PC after I was done with it and deleted the downloaded executable installation file, and confirmed that the installation folder was deleted as well.

4. Lastly, I did a system Restore to a point earlier than my installation of the KingoRoot program (you may want to create a Restore Point for this purpose beforehand), so that any other system files accidentally or intentionally corrupted or installed by KingRoot would also be restored to their original state or removed. Note that while System Restore often uninstalls programs that were installed after the Restore Point you go back to, it did NOT do so for KingoRoot.