In order to boot your recovery media, you need to reset the BIOS settings to factory default.
Start with the computer powered on and plugged-in to your charger.
Restart the computer by clicking Restart in the Start menu.
As the computer reboots, repeatedly tap the F1 key near the top left of the keyboard until you see the Entering Setup message.
At the BIOS lock screen, type the password ln15flavor (all lowercase) and press ENTER.
Use the left/right arrow keys to navigate to the Restart screen.
Use the up/down arrow keys to highlight
OS Optimized Defaults.
Press ENTER and use the arrow keys to select Enabled. Press ENTER.
Highlight Load Setup Defaults and press ENTER.
Select Yes and press ENTER.
Use the left/right arrow keys to navigate to the Security screen.
Highlight Password and press ENTER.
Highlight Supervisor Password and press ENTER.
Enter the current password, ln15flavor and press ENTER.
Enter a new password or leave it blank. Press ENTER.
Repeat the new password or leave it blank. Press ENTER.
Press ENTER to continue.
Press the ESC key at the top left of the keyboard.
Highlight the Security Chip option and press ENTER.
If the Clear Security Chip option is present, highlight it and press ENTER.
At the Clear encryption keys dialog, select Yes and press ENTER.
Press the ESC key.
Press the ESC key again.
Highlight Exit Saving Changes and press ENTER.
Highlight Yes and press ENTER.
When the system boots into BitLocker recovery, hold the power button down for five seconds to power it off.