Unlock bootloaderI have deleted this answer as i am not sure this Texas Instruments (WARNING - Factory Reset!TI) OMAP 4430 SoC is shipped with fastboot mode at all. Ususally Samsung devices have Odin Download mode, please follow this instructions instead
assuming you have already installed usb-drivers and fastboot.exehttps://twrp.me/samsung/samsunggalaxytab2gmsunified.html
press
Power
button until your tablet is offpress and hold together
Volume Down
+Power
buttonPress
Volume Up
to enter Download modeconnect USB cable to PC
then type from
cmd.exe
in fastboot directoryfastboot oem unlock
if your bootloader is unlocked you can delete cache from fastboot
`fastboot format:ext4 cache`
TWRP is available for your device, you can boot it and wipe cache(old answer still can be viewed here)
download twrp-2.8.5.0-p5100.tar
unpack recovery.img with 7-zip to fastboot directory
boot into twrp without flashing it
fastboot boot recovery.img
check the TWRP Menu / Advanced / Wipe