[Sony Xperia Miro, Tipo (Dual), J, E] Mc837:
Hello, as I decided today to root my first android phone and found it quite difficult to do, I'm writing a hopefully complete, noob friendly tutorial to root the Sony Xperia Miro (ST23i). Special thanks to Bin4ry's post and messmeww's post and XMoDXs1's incomplete post for the main ideas. If you have doubts/questions along the way please refer to Bin4ry's post (or messmeww's)!

Please remember that rooting your phone may void your warranty or brick it. Btw, hit that Thanks button if this helped!

Step 1 - Preparation

While I didn't care about the data on my phone, you probably should. Rooting can erase data (as I discovered the hard way). Delve into the forums and look for a good way to back up your data before proceeding. No help from me here.

Go into settings and tick the options "Unknown Sources" under Security and "USB Debugging" under Development Options. Remember to repeat this at the beginning on steps 2, 3 and 4 (unless already ticked). This operation will be referred to as "check the ticks".

Step 2 - Downgrading

If you go under Settings > About Phone you should see that the build number is 11.0.A.5.5. We need to downgrade the phone to an earlier version (11.0.A.2.10) to root it. This is done with the Flashtool. Download it here.

In the meanwhile, download the FTF files for both build numbers 11.0.A.2.10 and 11.0.A.5.5.

Once the Flashtool is downloaded, run and install it. Once you have done this, open the location of the installed Flashtool (e.g.: C:\Program Files (x86)\Flashtool) and open the "drivers" folder. Run the file Flashtool-drivers and follow the prompts until you reach a list, there select the option with Xperia U in it and the last 2 options of the list (both have "Super" in them I think). Then follow all other prompts to install these drivers.

Now check the ticks, plug in your phone via USB and run the Flashtool. Drag the 11.0.A.2.10 FTF file into the middle of the box and it should be loaded. (If this doesn't happen, return to the Flashtool install folder and run the "x10flasher" file, same thing, requires Java, then repeat). Once dragged, a window should pop up. DESELECT WIPE DATA! Then click "ok" and the Flashtool will begin flashing your phone. It will ask you to unplug the phone, turn it off, then replug it while holding the volume down button. At this point the Flashtool should automatically continue the process. Once the process is complete, unplug the phone once more and turn it on. It might take longer than usual, so don't panic. If you check, the build number should now be 11.0.A.2.10.

Step 3 - Rooting

Now we will root the phone using Bin4ry's Root with Restore (please, no mirrors by request of Bin4ry). Download it and unzip it in a folder on your desktop. Then, run CMD as an Administrator and type in the unzipped folder after "cd" (e.g.: "cd C:\Users\Mc837\Desktop\Root_by_Restore") and hit enter. Now type "runme", hit enter, type "1", hit enter, check the ticks, then plug in your phone. Follow the prompts and the phone will be rooted. When the phone turns again go to your applications one should now be "SuperSU". This means your phone is rooted.

Step 4 - Upgrading

Download the Root files here. Then, extract it to a folder on your desktop and run "01-local-prop" and follow the prompts. Now repeat Step 2 again but with the 11.0.A.5.5 FTF file, this will upgrade the firmware to your previous one. Unplug your phone and turn it on. Once on, you'll notice SuperSU is gone. Check the ticks and plug in your phone once more. In the same folder as "01-local-prop" locate and run "02-push-root-files". Follow the prompts and your phone will reboot by itself. Congratulations! Your phone is now rooted!

Step 5 - Enabling the MicroSD expansion slot (optional, not required for rooting)

Download "Root Browser Lite" from the Play Store. Open it and search for the file "vold.fstab" under System > etc. Once found, copy it as to have a backup, then open the file with a text editor and replace the last part (in code) with the following:

#MTD-BSP-LC-uSD_and_eMMC_coexistence-00 *[
dev_mount sdcard /mnt/sdcard auto /devices/platform/msm_sdcc.1/mmc_host
dev_mount ext_card /mnt/ext_card 16 /devices/platform/msm_sdcc.3/mmc_host/mmc0
#MTD-BSP-LC-uSD_and_eMMC_coexistence-00 *]

Now turn your phone on and off again. The internal memory will now be regarded as the external sd card (ext_sd) while the actual sd card will become what the phone calls sd_card! If you forgot to backup the file click here.

I hope this tutorial helped you. Hit the thanks button if you think so!