What This Guide Covers

This article explains how to troubleshoot and resolve the UEFI pre-boot exception error on Dell PowerEdge servers. It includes common causes, error indicators, and step-by-step solutions.

Quick Fix Summary

Update BIOS and iDRAC firmware to the latest versions.
Reseat or remove recently added hardware (e.g., PCIe cards, BOSS cards).
Clear NVRAM and perform a flea power drain before retrying updates.

Overview

The error “The system detected an exception during the UEFI pre-boot environment” typically appears during POST or firmware updates. It may result in a red screen or halt the boot process. This issue is often linked to hardware changes, outdated firmware, or incompatible components.

Error Indicators

Red screen during boot or firmware update.
iDRAC or Lifecycle Controller logs showing:
- A fatal error was detected on a component at bus X device Y function Z
- CPU page fault (type 0x0E) or Divide by Zero (Software)
- RIP addresses referencing .efi files (e.g., mnpdxe.efi, AHCI.EFI).
Lifecycle Controller error: System BIOS has halted (PST0208).

Possible Causes

Outdated BIOS or iDRAC firmware.
Recently installed or incompatible hardware (e.g., third-party PCIe adapters, BOSS cards).
Corrupted firmware update files.
Incorrect boot mode settings or NVRAM corruption.

Troubleshooting Steps

1. Update Firmware

Download the latest BIOS and iDRAC updates from Dell Support.
Apply updates via:
- Lifecycle Controller (F10 during POST).
- iDRAC web interface.
- Bootable ISO if the system cannot enter UEFI.

2. Reseat or Remove Hardware

Check logs for entries like bus X device Y function Z or slot numbers.
Power down the server and reseat PCIe cards, storage controllers, or BOSS cards.
Remove unsupported hardware if present.

3. Clear NVRAM

Power off the server.
Locate the NVRAM clear jumper (refer to the system board map under the lid).
Move the jumper to the clear position, power on until the jumper error appears, then power off and restore the jumper.
Reconfigure BIOS settings after clearing.

4. Perform Flea Power Drain

Shut down the server.
Disconnect power and network cables.
Hold the power button for 20 seconds.
Wait 3 minutes, reconnect cables, and power on.

5. Disable PCIe VDM (if applicable)

For systems with iDRAC9 firmware 4.00.00.00 and third-party PCIe adapters:

Use RACADM:

 racadm set iDRAC.PCIeVDM.Enable Disabledracadm serveraction powercycle

Upgrade iDRAC firmware to 4.10.10.10 or later, which removes PCIe VDM by default.

6. Reattempt Firmware Update

Redownload update packages to avoid corruption.
Run diagnostics via Lifecycle Controller (F10) and check logs for hardware errors.

Additional Notes

Always use Dell-certified hardware and firmware.
If installing VMware ESXi, ensure you use the Dell OEM ISO to avoid compatibility issues.
For persistent issues, contact Dell Support.

References

Affected Systems

Dell PowerEdge servers (12G–16G), including:
- R420, R720, R740xd, R760 series.
Operating environments:
- UEFI boot mode.
- VMware ESXi (ensure Dell OEM ISO).

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