In this article, I will guide you how to convert UEFI boot mode to Legacy on ASUS X550CA laptop, the mainboard is from American Megatrends. First, start the computer and press the F2 key repeatedly to enter BIOS mode. Here, first pay attention to the Security tab and pay attention to the " Secure Boot Control " setting, leave it in Disable mode. Step 2: Go to the Boot tab, here you need to pay attention to the Launch CSM setting option, leave it at Enable . After these two setup steps, you can boot your laptop in Legacy mode (In fact, you can use both UEFI and Legacy modes). Before pressing the F10 key to Save and exit BIOS mode, make sure you have Enable Legacy USB Support . Please set it up in the Advanced Tab --> USB Configuration . That's all.
