Gigabyte Z390 debug LED codes

Zeynel Abidin Öztürk -
2 years ago

Gigabyte Z390 motherboards come with an helpful debug LED that helps troubleshooting system issues. The debug LED is located bottom of the motherboard and helps you to pinpoint the source of the problem, in case your system doesn't boot or the monitor is blank. Such problems might occur because of many reasons like incompatible / faulty hardware, extreme overclocking settings, unplugged cables, wrong BIOS settings or not fully insterted RAM, etc.

Our system shows "A0" while using Windows, which means "IDE initialization is started"

During the boot, the LED rapidly shows various hexadecimal values, with every value representing a successful event or an error. Therefore the LED showing some value doesn't necessarily mean there is a problem. If your system can't boot, check the current LED value and compare it with the list below.

For more troubleshooting, refer to Gigabyte troubleshooting guide.

Note: We have taken the following list from the Gigabyte Z390 Aorus Ultra manual. These values probably mean the same for the other Z390 Aorus models, however I cannot confirm it since I don't have their manual.

Z390 Aorus Ultra debug LED codes

Regular boot

10 PEI Core is started.

11 Pre-memory CPU initialization is started.

12~14  Reserved.

15 Pre-memory North-Bridge initialization is started.

16~18  Reserved.

19 Pre-memory South-Bridge initialization is started.

1A~2A  Reserved.

2B~2F  Memory initialization.

31 Memory installed.

32~36  CPU PEI initialization.

37~3A  IOH PEI initialization.

3B~3E  PCH PEI initialization.

3F~4F  Reserved.

60 DXE Core is started.

61 NVRAM initialization.

62 Installation of the PCH runtime services.

63~67  CPU DXE initialization is started.

68 PCI host bridge initialization is started.

69 IOH DXE initialization.

6A IOH SMM initialization.

6B~6F  Reserved.

70 PCH DXE initialization.

71 PCH SMM initialization.

72 PCH devices initialization.

73~77  PCH DXE initialization (PCH module specific).

78 ACPI Core initialization.

79 CSM initialization is started.

7A~7F  Reserved for AMI use.

80~8F  Reserved for OEM use (OEM DXE initialization codes).

90 Phase transfer to BDS (Boot Device Selection) from DXE.

91 Issue event to connect drivers.

92 PCI Bus initialization is started.

93 PCI Bus hot plug initialization.

94 PCI Bus enumeration for detecting how many resources are requested.

95 Check PCI device requested resources.

96 Assign PCI device resources.

97 Console Output devices connect (ex. Monitor is lighted).

98 Console input devices connect (ex. PS2/USB keyboard/mouse are activated).

99 Super IO initialization.

9A USB initialization is started.

9B Issue reset during USB initialization process.

9C Detect and install all currently connected USB devices.

9D Activated all currently connected USB devices.

9E~9F  Reserved.

A0 IDE initialization is started.

A1 Issue reset during IDE initialization process.

A2 Detect and install all currently connected IDE devices.

A3 Activated all currently connected IDE devices.

A4 SCSI initialization is started.

A5 Issue reset during SCSI initialization process.

A6 Detect and install all currently connected SCSI devices.

A7 Activated all currently connected SCSI devices.

A8 Verify password if needed.

A9 BIOS Setup is started.

AA Reserved.

AB Wait user command in BIOS Setup.

AC Reserved.

AD Issue Ready to boot event for OS boot.

AE Boot to Legacy OS.

AF Exit Boot Services.

B0 Runtime AP installation begins.

B1 Runtime AP installation ends.

B2 Legacy Option ROM initialization.

B3 System reset if needed.

B4 USB device hot plug-in.

B5 PCI device hot plug.

B6 Clean-up of NVRAM.

B7 Reconfigure NVRAM settings.

B8~BF  Reserved.

C0~CF  Reserved.

S3 Resume

E0 S3 Resume is started (called from DXE IPL).

E1 Fill boot script data for S3 resume.

E2 Initializes VGA for S3 resume.

E3 OS S3 wake vector call.


F0 Recovery mode will be triggered due to invalid firmware volume detection.

F1 Recovery mode will be triggered by user decision.

F2 Recovery is started.

F3 Recovery firmware image is found.

F4 Recovery firmware image is loaded.

F5~F7  Reserved for future AMI progress codes.


50~55  Memory initialization error occurs.

56 Invalid CPU type or speed.

57 CPU mismatch.

58 CPU self test failed or possible CPU cache error.

59 CPU micro-code is not found or micro-code update is failed.

5A Internal CPU error.

5B Reset PPI is failed.

5C~5F  Reserved.

D0 CPU initialization error.

D1 IOH initialization error.

D2 PCH initialization error.

D3 Some of the Architectural Protocols are not available.

D4 PCI resource allocation error. Out of Resources.

D5 No Space for Legacy Option ROM initialization.

D6 No Console Output Devices are found.

D7 No Console Input Devices are found.

D8 It is an invalid password.

D9~DA Can't load Boot Option.

DB Flash update is failed.

DC Reset protocol is failed.

DE~DF  Reserved.

E8 S3 resume is failed.

E9 S3 Resume PPI is not found.

EA S3 Resume Boot Script is invalid.

EB S3 OS Wake call is failed.

EC~EF  Reserved.

F8 Recovery PPI is invalid.

F9 Recovery capsule is not found.

FA Invalid recovery capsule.

FB~FF  Reserved.


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Guest says 6 months ago 12/20/2020 1:52 PM
What does FF "reserved" ACTUALLY mean? I've got that code but everything is working fine.

Zeynel (defkey) says in reply to Guest : 6 months ago 12/22/2020 1:00 PM
If everything is fine, it may not be a problem at all. What I see is latest code (A0 - IDE init started) remains when Windows is running.

I may be wrong but what I get from "reserved" is this may have some meaning user won't necessarly need to know or reserverd code that may be used in future after firmware updates.

Guest says 7 months ago 11/15/2020 7:38 PM
i have code 25 too

CJ says 7 months ago 11/13/2020 9:20 PM
I got the 25 code on my Z390 Master, does anyone know what this means??

Guest says in reply to CJ : 7 months ago 11/15/2020 7:58 PM
steps i took was open APPCENT, and installed all updates, restarted computer, noticed how intel storage technoligy app at the top said it would be supported any longer, so uninstalled it. and the dubug led returned to AO during boot and startup, but as soon as it had fully loaded all apps and i opened microsoft edge browser to come here, it returned to 25 :S WHAT THE ****

Guest says in reply to CJ : 7 months ago 11/15/2020 8:34 AM
Same here, only changes I've made are upgrading to Windows 10 Ver 20H2 and I installed the latest Gigabyte App Centre. Only then did I notice the debug led was showing 25. Could be a coincidence but 🤷‍♂️ who knows. PC seems to be running fine.

Guest says in reply to CJ : 7 months ago 11/14/2020 8:56 PM
same, changed to 25 today

Guest says in reply to CJ : 7 months ago 11/14/2020 5:23 PM
I have the same problem, that wasn't there 24h ago.

Guest says 8 months ago 10/8/2020 12:46 PM
can you help me with the A4 error?

Guest says 15 months ago 3/7/2020 8:28 AM
Mine says D4 but not experiencing any issues. 🤷‍♀️🤷‍♀️🤷‍♀️

romboy50 says 18 months ago 1/3/2020 4:27 PM
I have a Gigabyte Z390 ultra motherboard and the last thing it says is A0 in windows so is every thing good?

Zeynel (defkey) says in reply to romboy50 : 18 months ago 1/3/2020 5:09 PM
By the way, not all codes are errors, I see many of them are for information. I think, if for example your system locked up during "A0" it would mean something is wrong with IDE. But it's not the case.

Zeynel (defkey) says in reply to romboy50 : 18 months ago 1/3/2020 5:07 PM
Probably yes. Currently mine also says A0, as I also stated in the article. It means "IDE initialization is started". That's probably last thing UEFI BIOS made before Windows take over, so it stays like that.

tes says 19 months ago 11/28/2019 11:20 PM
what 00 led code means?

Please let me know.


Zeynel (defkey) says in reply to tes : 19 months ago 12/1/2019 11:32 PM
It doesn't appear in the list, can it be D0 which means "CPU initialization error"?