Resetting your Acer Iconia B1 tablet recovery hard reset
Hard Reset Iconia B1 tab
Turn off Iconia B1 tab.
Press Volume UP + power on the device.
Select "SD Image update mode" using Volume down and select with power key.
In the next menu select wipe data / factory reset with volume key and press power to select, then yes --- delete all data press power.
All data will be deleted! unlock your forgotten lock pattern PIN password on Iconia B1 TAB.
After all done select reboot system now.