Download Latin America Generic Sony Xperia Z3 Tablet Compact Wi-Fi SGP611 Stock Android Marshmallow 6.0.1 Firmware 23.5.A.0.575 just Make Sure you have installed all drivers in your computer And also here you can found complete Guide for How to Flash this Rom.
How To Install Instructions For Stock Android 6.0.1 Rom for Sony Xperia Z3 Tablet SGP611 23.5.A.0.575
a) Just Start with check your Device firmware version (if device have Newest Version, you do not need this guideline)
b) download Xperia Flashtool From HERE
c) download Latin-America Generic Marshmallow 6.0.1 for Sony XPERIA Z3 Tablet SGP611
d) now paste the Firmware ftf file downloaded in step c) to folder „Firmware“ included within the XPERIA Flash-tool
e) Start The XPERIA Flash-tool, click on Install and Select downloaded firmware, After than click on OK. IMPORTANT if you don’t want to delete any Data of your Cell-Phone, simply unchecked installing userdata.Sin file. All Data will save in your Device, however usually it might probably reason further Issues. So it is Recommended (and that i Suggested that) to do the backup of your Device data, than proceed with Clean Installing after then restore your Personal data.
F) Just Power off your Mobile and when Flashtool Show’s pop up window, connect Device to computer with Keep Pressing volume down Key.
g) after Some Minutes all Flash Procedure is Done and your Phone will get the new firmware
Unlock Bootlaoder Guide HERE
Lock Bootloader Guide HERE
Download Marshmallow 6.0.1 Stock Rom For Latin-America Generic Xperia Z3 Tablet Wifi SGP611 Firmware FTF
SGP611_23.5.A.0.575_R3 Latin America.ftf HERE