To boot from USB on Lenovo ideapad:
1. Shut down the computer.
2. Press the power button, then keep pressing the F2 key until you are taken to the bios menu.
3. Go to the Boot tab, and set the Boot priority to Legacy Support
4. Make sure the USB boot is on Enable, and set the USB the top priority on Legacy boot menu.
5. Save the changes and exit. then shut down the computer.
6. connect the USB, turn on the laptop and press the F12 key straight away, this will bring you to the boot menu to select the USB.
See how to do it here:
* If F2 foes not work: if the F2 key did not work imaybe it is because "Fast Boot" is activated, Which makes access to BIOS impossible until that it turned off.
You will need to disable "Fast Boot" from the power button menu:
1. Make sure the laptop is turned off. Not in Hibernate or Sleep mode.
2. Press the power button and hold it down. The system should emit three short beeps from the speaker, or headphones if you have them plugged in.
3. After the beeps, release the power button 'before' the 4-second shutdown override.
4. The power button menu should now display.
5. Press F3 to disable Fast Boot and you should be able to access BIOS now.
(By the same instructions as above, pressing the F2 button).