Ensure you are flashing a completely stock, official firmware package. Cached data conflict
Before resorting to a full firmware flash, you can verify the status of your hardware using Sony's built-in service menu: Service Menu Code *#*#73788423#*#* sony s1 service flash file verified
Press and hold the button (or the designated boot key for your variant). Ensure you are flashing a completely stock, official
Service Drivers : You must install the for your computer to recognize the tablet in flash mode. sony s1 service flash file verified
(the specific "flash key" can vary, but Volume Down is standard for most S1-protocol devices).
: Look for the Stock ROM firmware (usually in .ftf or specific service formats) from reputable databases like Xperia Stock ROM