With the boot path aligned to the supported configuration, the PPC3100 starts Debian 10 from the new CF card in UEFI mode while retaining the hypervisor. A legacy result cannot be created merely by changing an installation option: boot mode depends on both the PPC3100 firmware selection and the bootloader written to the card. For the Debian 10 and hypervisor combination described here, use UEFI.
What boot result should you expect?
The B&R installation completed successfully, including the hypervisor space, but the resulting CF card booted only through UEFI. That outcome identifies a configuration boundary rather than a failed Debian installation. With the hypervisor in this boot chain, UEFI is the supported mode.
Separate three questions before changing anything:
- Which mode does the PPC3100 BIOS select: legacy or UEFI?
- Which boot path did the Debian 10 installation write to the CF card?
- Does the hypervisor support that complete firmware-to-operating-system path?
The BIOS selection alone does not convert a UEFI installation into a legacy installation. Likewise, rewriting the card cannot make an unsupported hypervisor path valid. Look at the boot indication first, then follow the chain from firmware to bootloader to hypervisor to Debian.
Is the PPC3100 firmware selecting UEFI or legacy?
Enter the PPC3100 BIOS and read the configured boot mode. The PPC3100 firmware can select legacy or UEFI operation, but the selectable value must match a bootloader present on the CF card.
| Signal or reading | Where to read it | Wrong-value symptom |
|---|---|---|
| Selected boot mode | PPC3100 BIOS | A legacy-only selection cannot start media containing only a UEFI boot path; a UEFI-only selection cannot use a legacy-only loader. |
| Bootloader type on the CF card | Card layout and installed boot files | The card is visible but does not offer a usable boot path for the selected firmware mode. |
| Hypervisor present | Installed system layout | Changing to a boot path unsupported by the hypervisor prevents the complete stack from starting. |
| Debian start result | Boot screen and operating-system startup | Failure before Debian begins points to firmware, media, bootloader, or hypervisor compatibility rather than Debian services. |
If the BIOS already selects UEFI and Debian starts, continue with the UEFI configuration. If the BIOS selects legacy and the card does not start, inspect the card's bootloader before treating the BIOS as faulty. If the BIOS setting cannot be changed, check whether the active platform configuration or hypervisor constrains the choice.
Does the CF card contain a legacy boot path?
A CF card does not have an independent “legacy mode” flag that converts its contents. Firmware discovers and executes boot code using one of two different mechanisms. UEFI media normally provides an EFI system partition and a UEFI executable; legacy firmware expects BIOS-compatible boot code and a matching bootloader installation.
Inspect the card layout rather than relying on the installer completion message. The reading that matters is whether the card contains a BIOS-compatible loader in addition to, or instead of, its UEFI files. A successful installation proves that files were deployed; it does not prove that both firmware paths were created.
If the card contains only the UEFI path, selecting legacy in BIOS will not make it boot. Return to the installation-image decision. Use an installer that explicitly provides the required loader, or retain UEFI. Do not attempt to repair this mismatch by changing Debian services, network settings, or application configuration because those layers have not started yet.
Is the hypervisor part of the required configuration?
The hypervisor sits between the platform boot process and the operating-system environment. Its supported startup mechanism therefore controls the whole chain. In this PPC3100 configuration, using Debian 10 together with the hypervisor requires UEFI.
If the hypervisor is required, the decision tree ends at UEFI: configure the PPC3100 BIOS for UEFI, retain the UEFI Debian installation, and verify that both the hypervisor and Debian start. Repeatedly recreating the CF card will not produce a supported legacy stack from this installation path.
If legacy boot is an external project requirement, treat it as a different system architecture. First determine whether the hypervisor may be removed. Then obtain confirmation that the intended Debian image includes a BIOS-compatible loader and that the exact platform configuration supports it. Removing the hypervisor or changing the image is an architectural change, not a boot-option adjustment.
Why can the boot-mode option be unavailable?
An unavailable installer option means the selected installation workflow does not expose an alternative bootloader path. The BIOS and installer perform different jobs: the BIOS selects how it searches for boot code, while the installer decides which boot code exists on the CF card.
Read the restriction at the layer where it appears. If the installer offers only UEFI output, changing the BIOS cannot add a legacy loader. If the BIOS prevents changing its selection, record the active configuration and whether the hypervisor is enabled. If a legacy-capable card still does not appear as a legacy boot target, check media detection and bootloader installation before changing unrelated operating-system settings.
Avoid mixed changes. Changing the BIOS, rebuilding the card, and altering the hypervisor configuration at once removes the evidence needed to locate the mismatch. Take one reading, make one change, and observe where startup stops.
How do you resolve and verify the supported branch?
- Confirm that the hypervisor is required for the PPC3100 installation.
- Enter the PPC3100 BIOS and select UEFI boot mode. If the control is unavailable, record the displayed mode and active platform configuration before proceeding.
- Install Debian 10 to the new CF card using the B&R installation workflow that also creates the hypervisor space.
- Place the CF card in the target PPC3100 and select it as the boot device without changing unrelated BIOS settings.
- Observe the startup sequence. Verify that firmware recognizes the card, the hypervisor starts, and control passes to Debian.
- Restart the controller from a powered-down state and repeat the check. A warm restart alone can hide boot-order or media-discovery problems.
The resolving branch is verified only when the same CF card starts through UEFI, the hypervisor initializes, and Debian reaches its normal operating state after a cold start. If startup stops before Debian, stay with firmware, card layout, bootloader, and hypervisor checks. If Debian begins loading and then fails, continue with operating-system diagnostics rather than revisiting the firmware mode.
Frequently Asked Questions
What happens if I select legacy mode for the UEFI CF card?
The PPC3100 will not find a compatible legacy bootloader on media created only for UEFI. Selecting a firmware mode does not rewrite the CF card.
What happens if I keep the hypervisor but require legacy boot?
The requested combination falls outside the supported UEFI boot path described for Debian 10 with the hypervisor. Retain UEFI or obtain an explicitly supported alternative architecture before rebuilding the card.
What happens if Debian installs successfully but the card will not boot?
Check the PPC3100 BIOS mode against the bootloader written to the CF card. A completed file installation does not prove that the firmware and media use the same startup mechanism.
When should I stop changing settings and contact support?
Stop when UEFI is selected, the card has been recreated through the intended B&R workflow, and startup still fails before Debian, or when the BIOS mode remains unavailable. Record the boot screen, BIOS selection, card layout, hypervisor presence, and the exact stage where startup stops. Escalate those observations to official B&R support for confirmation of the supported platform configuration.