What is UEFI Variable?
Quick note explaining UEFI Variable for BIOS/UEFI and embedded firmware readers.
What is UEFI Variable?
A UEFI Variable is a named key-value object identified by a name, vendor GUID, attributes, and data.
Why it matters
- Explains the core language used in BIOS/UEFI source and logs.
- Helps identify where a concept appears in the boot flow.
- Serves as a bridge between specification terms and real firmware debugging.
Practical example
Example: when reading a boot log, search for UEFI Variable-related messages and note which phase produced them before jumping into source code.
Quick checklist
- Which phase is the last confirmed point in the log?
- Is there enough context around the failure?
- Can UEFI Shell output confirm the same state?
Quick takeaway
UEFI Variable is a small concept, but it often becomes important when reading logs or debugging real firmware.
Related notes
- What is UEFI Variable Store?
- What is Variable Attribute?
- What is NVRAM?
- What is Runtime Services?
- What is Variable Store Full?
Public references
- UEFI Specification 2.11 — Runtime Services
- UEFI Specification 2.11
- UEFI PI Specification 1.9
- EDK II source code
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Quick note explaining Runtime Services for BIOS/UEFI and embedded firmware readers.
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Quick note explaining GUID in UEFI for BIOS/UEFI and embedded firmware readers.
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