CCNA BIOS / UEFI Questions

A failing or depleted CMOS battery cannot retain BIOS settings, causing defaults to load and often requiring user intervention at boot. This is a common issue that leads to the 'Press F1' prompt. The question tests understanding of CMOS battery function in maintaining firmware settings.

If the new motherboard defaults to UEFI mode but the SSD was formatted with an MBR partition table (for Legacy), the system cannot boot. Changing to Legacy/CSM mode or reinstalling with GPT is needed. This tests understanding of partition table and boot mode compatibility.

NVMe drives require UEFI mode because legacy BIOS lacks the necessary driver support for NVMe controllers. Enabling UEFI boot mode and disabling legacy/CSM allows the firmware to initialize the NVMe drive correctly. This question tests understanding of UEFI's role in supporting modern storage interfaces.

If the SATA mode is changed from AHCI to IDE, the OS driver may not load, causing a boot failure. This can happen after a CMOS reset or accidental BIOS change. The question tests understanding of SATA controller modes and their impact on booting.

Virtualization support must be enabled in the CPU's firmware settings (e.g., Intel VT-x or AMD-V) before the OS can use it. The OS setting alone is insufficient. This question tests knowledge of firmware-level CPU features.

A CMOS checksum error indicates that the BIOS/UEFI settings are not being retained, often due to a failing or dead CMOS battery. This causes time/date resets and boot delays as the firmware re-detects hardware. This tests knowledge of common CMOS-related symptoms.

Most modern UEFI systems allow you to press a key (like F12, F2, Esc) during startup to access a one-time boot menu. This lets you select the boot device for that session without permanently changing the boot order.

When a drive is recognized in UEFI but not in the OS, it often means the drive is not initialized or formatted. Disk Management can initialize the drive and assign a file system, making it usable by the OS.

A firmware update can reset UEFI settings to defaults, including boot mode. If the drive was formatted for Legacy (CSM) but the system now defaults to UEFI, or vice versa, the bootloader won't be found. This tests understanding of boot mode compatibility.

Windows 11 requires UEFI with GPT partition table and Secure Boot. The error indicates the drive is using MBR, which is incompatible with UEFI. The technician should either convert the drive to GPT using diskpart or reinitialize it as GPT during installation.

Intel VT-x or AMD-V is the hardware virtualization feature that must be enabled in the CPU configuration section of UEFI. Without it, virtual machines will run slowly or fail to start. This tests knowledge of common UEFI settings for virtualization.

TPM (Trusted Platform Module) is often disabled by default in the UEFI firmware. It must be enabled in the security settings of the UEFI. Additionally, the system must be set to UEFI mode (not Legacy) with Secure Boot enabled for Windows 11 compatibility.

If the system has integrated graphics and a discrete card, the UEFI may default to the integrated output. Changing the primary video adapter to PCIe/ PEG forces the system to use the new card. This tests understanding of video initialization order in UEFI.

When using a hardware RAID controller, the OS installer needs the appropriate driver to recognize the RAID volume. Without the driver, the installer sees individual drives instead of the array. The technician must load the RAID driver during installation, typically by pressing a key (e.g., F6) or browsing for the driver.

Windows 11 requires TPM 2.0, which may be disabled in UEFI by default. The technician must enable the TPM device in the security settings. This tests knowledge of TPM configuration and its role in system requirements.

Many motherboards have a dual BIOS feature where a backup chip stores a factory-default firmware. Switching to the backup BIOS restores functionality without needing external tools. This scenario tests knowledge of BIOS recovery mechanisms and the importance of redundant firmware.

Secure Boot enforces cryptographic verification of bootloaders, preventing unauthorized code from running during boot. This is a key security feature in UEFI. The question tests understanding of Secure Boot's purpose and implementation.

The CMOS battery maintains the real-time clock and UEFI settings when power is off. If it fails, the time resets and settings may be lost. This tests the ability to distinguish between battery failure and other hardware issues.

If Secure Boot is enabled and the USB is not signed or UEFI-bootable, the system may ignore it. Alternatively, the boot order may not include USB. This tests understanding of boot security and order settings.

Beep codes are used by the BIOS/UEFI to indicate hardware errors during POST. Three beeps typically indicate a memory (RAM) error. The technician should reseat or test the RAM sticks individually to isolate the faulty module.

Many motherboards require a BIOS update to support newer CPU microcode. Without it, the system cannot initialize the CPU. This question tests knowledge of CPU compatibility and the role of firmware updates in hardware support.

This scenario describes thermal shutdown protection. The BIOS/UEFI monitors CPU temperature via sensors and will shut down the system to prevent damage if temperatures exceed safe thresholds. The delay before restarting allows the CPU to cool down.

The CMOS checksum error indicates that the BIOS settings are corrupted or not being retained. The date/time resetting after power-off points to a failing or dead CMOS battery, which powers the volatile memory that stores these settings when the system is off.

Secure Boot ensures that only software signed with trusted certificates can boot. This prevents unauthorized bootloaders and rootkits. This tests knowledge of UEFI security features.

To prevent unauthorized booting from external media, the technician must set a boot order that prioritizes the internal SSD and disable other boot devices. Additionally, setting a UEFI administrator password prevents unauthorized users from changing these settings.

For systems with more than 4 GB of RAM, the OS must be 64-bit, and the firmware must have memory remapping enabled. This feature allows the UEFI to reassign memory addresses previously reserved for PCI devices, making the full RAM capacity available to the OS.

Three beeps in many BIOS versions (especially AMI and Award) indicate a memory error, such as a faulty or improperly seated RAM module. This is a standard POST diagnostic code. The question tests basic familiarity with beep codes.

UEFI requires GPT partition table to boot, and GPT supports drives larger than 2 TB. Legacy BIOS with MBR cannot address beyond 2 TB. This question reinforces the relationship between UEFI and GPT for large drives.

The correct answer is to check the SATA configuration mode. If the SATA controller is set to RAID or AHCI when the drive requires the other, or if it's disabled, the drive may not be detected. This tests understanding of how UEFI/BIOS settings affect hardware enumeration.

The SSD may not be initialized with a GPT partition table or may lack an EFI system partition, making it invisible to the UEFI boot manager. The technician should check the partition style and ensure the SSD is properly formatted for UEFI boot. This question tests advanced knowledge of UEFI boot requirements.