Download And Flash Taiwan Generic Sony Xperia Z2 Tablet Wi-Fi SGP512 Android Marshmallow 6.0.1 Firmware Rom Version 23.5.A.0.575 Before Flashing just confirm First you have Successfully Installed Sony USB Driver’s in your Computer And also Installed Latest Version of Flashtool.
Full Guideline For Flash Marshmallow Stock Rom for Sony Xperia Z2 Tablet Wifi SGP512 23.5.A.0.575
a) Check your Phone Firmware version if your device already have latest one just skip this tutorial
b) download Newest Sony Xperia Flashtool From HERE
c) download Taiwan Generic Marshmallow 6.0.1 for Sony XPERIA Z2 Tablet SGP512
d) now paste the Firmware ftf file which you downloaded in step c) to folder „Firmware“ included within the Sony Xperia Flash-tool
e) Now Run The XPERIA Flash-tool, click on Install and Select downloaded firmware, After than click on OK. Useful Info if you do not want to delete any Data of your Mobile, simply unchecked installing userdata.Sin file. All Phone Data will save in your Mobile, however usually it might probably reason further Issues. So it is Preferred (and that i Recommended that) to do the backup of your Device data, than proceed with Smooth & Clean Flashing after then restore your Personal data.
F) Turn OFF your Device and when Flashtool Show’s pop up window, connect Mobile to computer with Holding volume down Key.
g) after Some Time all Flash Instructions is Compeleted and your Cell-Phone will get the Latest firmware
Unlock Bootlaoder Guide HERE
Lock Bootloader Guide HERE
Download Android Marshmallow 6.0.1 Stock Firmware FTF For Taiwan Generic Xperia Z2 Tablet Wifi SGP512
SGP512_23.5.A.0.575_R1 Taiwan.ftf HERE