[Xperia Z2 Tablet Q&A, Help & Troubleshooting] Elliander:
It's a nice idea, but it doesn't work. "operation not permitted". Here's the output from Easy Root:

==============================================
= =
= Easy Root Tool v11 =
= Supports various Xperia devices =
= created by zxz0O0 =
= =
= http://xdaforums.com/ =
= showthread.php?p=53448680 =
= =
= Many thanks to: =
= - [NUT] =
= - geohot =
= - MohammadAG =
= - cubeundcube =
= - nhnt11 =
= - xsacha =
= =
==============================================

=============================================
tr.apk not found. Trying to download from
https://towelroot.com/tr.apk
=============================================
######################################################################## 100.0%

=============================================
Extracting libexploit.so using 7z
=============================================
OK

* daemon not running. starting it now on port 5037 *
* daemon started successfully *
=============================================
Waiting for Device, connect USB cable now...
Make sure you have only one Android device connected
BlueStacks emulator can also cause problems
=============================================
Device found

=============================================
Getting device variables
=============================================
Device model is SGP561
Firmware is 17.1.D.0.417

=============================================
Sending files
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221 KB/s (1585 bytes in 0.007s)
3452 KB/s (657704 bytes in 0.186s)
368 KB/s (1133 bytes in 0.003s)
1854 KB/s (9496 bytes in 0.005s)
2670 KB/s (13672 bytes in 0.005s)

Copying kernel module...
2805 KB/s (34473 bytes in 0.012s)
249 KB/s (767 bytes in 0.003s)
1659 KB/s (13592 bytes in 0.008s)
Kernel version is 3.4.0-perf-g31245c3
Version does not match 3.4.0-perf-ge4322cd, needs patching...
1+0 records in
0+1 records out
19 bytes transferred in 0.001 secs (19000 bytes/sec)
Kernel module patched.

modulecrcpatch (by zxz0O0)

module_layout: patched to 0xCFADE050
__aeabi_unwind_cpp_pr1: match
kallsyms_lookup_name: not found
printk: not found
mem_text_write_kernel_word: not found
__aeabi_unwind_cpp_pr0: match
successfully patched

=============================================
Loading towelzxperia
=============================================
2211 KB/s (13592 bytes in 0.006s)
3211 KB/s (197320 bytes in 0.060s)
=============================================

Waiting for towelzxperia to exploit...

towelzxperia by zxz0O0 (EasyRootTool Version)
libexploit by geohot

libzxploit.so created
doing the magic
creating vm (loljavasucks)
mount: Operation not permitted
cleaning up

Also, as I said before, my firmware is 17.1.D.0.417. Yours can't be the latest firmware if my firmware is a higher number. I'm still stuck in this limbo where some apps think it's rooted and other apps don't.

EDIT: Despite the error it gave me, I tried installing SuperSU by chainfire again and I seemed to get farther at least, but it failed. Rebooting to try again.

EDIT 2: It also gave me this error on my computer when I rebooted the device:

Checking if device is rooted...
error: device not found
Error: device not rooted
Press any key to continue . . .

But when I went into SuperSU it didn't give me any errors. I went into Root Explorer and it actually asked me if I wanted to grant super user privileges, but I don't think it's fully rooted though. The root folder is empty, and although I can see the files of other directories, it fails to touch a few things. I kind of expected that would happen to bootanimation.zip, but I also can't edit Platform.XML to restore write permissions. I have done this before on other devices so I know I was doing it correctly, but it just failed to edit. I even tried an app to do so, but it also failed. It's rooted enough to see the files and open them. I can even copy files otherwise hidden and it appears to be able to mount as read/write. It's just that it always fails to do anything with it.

I then went and installed "Mount /system (rw / ro)" and although it appeared to work successfully after granting it super user privileges, it still didn't allow me to edit the files in root explorer, so I installed FX and and it's root add on module. I tried to edit the files, but it wasn't mounted as "Read/Write" as far as it's concerned and when I tried doing so within it's menu it just said "Error" The operation could not be completed"

So... am I rooted or not? Easy Root definitely helped me get farther, but not far enough to actually do what I needed the root to do.

EDIT 3: After a few minutes, for some unknown reason, Root Explorer allowed me to edit Platform.XML to add <group gid=”media_rw” /> under WRITE_EXTERNAL_STORAGE (still won't work in FX though) and of course I still can't edit bootanimation.zip, but as a test I successfully moved some files from the internal memory to the 128 GB micoSD so I'm at least rooted enough to restore access to the SD card so I will give it some time to see how much I can do with it.

P.S. - There is a forum bug. When I edit posts on a tablet there are no problems, but when I do so on a computer it tells me I have to wait 5 minutes before writing a new post to prevent spam - even though it's not a new post, it's an edit of an old post. Just like there is a weird thing where it will let me post links in a tablet, but not in a PC. Unfortunately, there doesn't appear to be any bug report form or moderator contact links so just putting it here.