Keyboard backlight not working — request patch for SN ZZMinBXHY4H241101685

Hello,

I have a Chuwi MiniBook X with the following specifications:

  • Serial Number: ZZMinBXHY4H241101685

  • BIOS Version: DNN20 V2.22

  • Firmware Revision (EC): 0.18

  • OS: Fedora 42, kernel 6.16.9-200.fc42.x86_64

After the latest BIOS update, my keyboard backlight stopped working — no /sys/class/leds/*kbd* entries appear, and rolling back the kernel did not restore the lights.

I’ve attached my key outputs for reference:

BIOS Information         Vendor: American Megatrends International, LLC.         Version: DNN20 V2.22         Release Date: 06/12/2024         Address: 0xF0000         Runtime Size: 64 kB         ROM Size: 0 MB         Characteristics:                 PCI is supported                 BIOS is upgradeable                 BIOS shadowing is allowed                 Boot from CD is supported                 Selectable boot is supported                 BIOS ROM is socketed                 EDD is supported                 Japanese floppy for NEC 9800 1.2 MB is supported (int 13h)                 Japanese floppy for Toshiba 1.2 MB is supported (int 13h)                 5.25"/360 kB floppy services are supported (int 13h)                 5.25"/1.2 MB floppy services are supported (int 13h)                 3.5"/720 kB floppy services are supported (int 13h)                 3.5"/2.88 MB floppy services are supported (int 13h)                 Print screen service is supported (int 5h)                 8042 keyboard services are supported (int 9h)                 Serial services are supported (int 14h)                 Printer services are supported (int 17h)                 CGA/mono video services are supported (int 10h)                 ACPI is supported                 USB legacy is supported                 BIOS boot specification is supported                 Targeted content distribution is supported                 UEFI is supported         BIOS Revision: 2.22         Firmware Revision: 0.18  # dmidecode 3.6 Getting SMBIOS data from sysfs. SMBIOS 3.5.0 present.  Handle 0x0001, DMI type 1, 27 bytes System Information         Manufacturer: CHUWI Innovation And Technology(ShenZhen)co.,Ltd         Product Name: MiniBook X         Version: Default string         Serial Number: ZZMinBXHY4H241101685         UUID: 9b76ab00-b627-11ef-8466-e40bec672a00         Wake-up Type: Power Switch         SKU Number: Default string         Family: Default string  CHUWI Innovation And Technology(ShenZhen)co.,Ltd MiniBook X │ ├─N100: │     Device ID:          4bde70ba4e39b28f9eab1628f9dd6e6244c03027 │     Current version:    0x0000001d │     Vendor:             Intel │     GUIDs:              90cc499c-3166-5538-b337-ac47d715d50b ← CPUID\PRO_0&FAM_06&MOD_BE │                         dcb3a326-6c55-59ef-a947-d5ae46f7b4ec ← CPUID\PRO_0&FAM_06&MOD_BE&STP_0 │     Device Flags:       • Internal device │    ├─RS512GSSD510: │     Device ID:          71b677ca0f1bc2c5b804fa1d59e52064ce589293 │     Summary:            NVM Express solid state drive │     Current version:    W0428A0 │     Vendor:             Silicon Motion, Inc. (PCI:0x126F) │     Serial Number:      EC051301A001301 │     GUIDs:              eb4c6074-9dc2-57ae-bd43-1119ad6080f5 ← NVME\VEN_126F&DEV_2263 │                         165a89d1-acc2-51c7-92b9-300207a5409c ← NVME\VEN_126F&DEV_2263&SUBSYS_126F2263 │                         4371a899-9413-5484-a2f8-7fbea5cd9a04 ← RS512GSSD510 │     Device Flags:       • Internal device │                         • Updatable │                         • System requires external power source │                         • Needs a reboot after installation │                         • Device is usable for the duration of the update │                         • Can tag for emulation │    ├─SBAT: │     Device ID:          6469856584e2f5873b2f148302e46c9313c7d054 │     Summary:            Generation number based revocation mechanism │     Current version:    1.5.4 │     Vendor:             OS:fedora │     GUID:               92f517f7-73b9-5373-a9b2-9da4b726178e ← UEFI\OS_fedora&VAR_SbatLevelRT │     Device Flags:       • Updatable │                         • Needs a reboot after installation │                         • Signed Payload │    ├─System Firmware: │ │   Device ID:          5f9a565add4861691d58227717547b14b4290bfb │ │   Summary:            UEFI System Resource Table device (Updated via capsule-on-disk) │ │   Current version:    222 │ │   Minimum Version:    222 │ │   Vendor:             CHUWI Innovation And Technology(ShenZhen)co.,Ltd (DMI:American Megatrends International, LLC.) │ │   Update State:       Success │ │   GUID:               f321772f-34f1-4bd5-94da-d4238eece7fb │ │   Device Flags:       • Internal device │ │                       • Updatable │ │                       • System requires external power source │ │                       • Needs a reboot after installation │ │                       • Cryptographic hash verification is available │ │                       • Device is usable for the duration of the update │ │   Device Requests:    • Message │ │  │ ├─Oem Secure Boot PK 20231007: │ │     Device ID:        6924110cde4fa051bfdc600a60620dc7aa9d3c6a │ │     Summary:          UEFI Platform Key │ │     Current version:  2023 │ │     Vendor:           Unknown │ │     GUID:             bb2c23b1-844c-5d3b-8019-8cf9bca9f91d ← UEFI\CRT_9BD860257159E2CF0DE657A93C9D51AD08D25A5C │ │     Device Flags:     • Internal device │ │    │ ├─UEFI Key Exchange Key: │ │ │   Device ID:        2a4c23bfb79b5dabe474cb7b1b3e604645d6f9c6 │ │ │   Device Flags:     • Internal device │ │ │  │ │ ├─KEK CA: │ │ │     Device ID:      b7a1d3d90faa1f6275d9a98da4fb3be7118e61c7 │ │ │     Current version: 2023 │ │ │     Vendor:         Microsoft (UEFI:Microsoft) │ │ │     GUIDs:          814e950f-1449-566a-a190-42c9d3a3a2df ← UEFI\VENDOR_Microsoft&NAME_Microsoft-KEK-CA │ │ │                     cd94ec34-7163-5f27-8549-1bd4b7872ae8 ← UEFI\CRT_DEC64D7746D983DB3774829A00BF829D9F19E9CF │ │ │     Device Flags:   • Internal device │ │ │                     • Updatable │ │ │                     • Needs a reboot after installation │ │ │                     • Device is usable for the duration of the update │ │ │                     • Signed Payload │ │ │                     • Can tag for emulation │ │ │    │ │ └─Oem Secure Boot KEK 20231007: │ │       Device ID:      97f55f80051a0c5bed699a468c4a775699cedb48 │ │       Current version: 2023 │ │       Vendor:         Unknown │ │       Update Error:   No vendor ID set │ │       GUID:           a1bb140c-8e61-5410-ba94-5400be13cbde ← UEFI\CRT_19A0C9F78DB8195D20024E9E0E881A0109F17D7E │ │       Device Flags:   • Internal device │ │                       • Needs a reboot after installation │ │                       • Device is usable for the duration of the update │ │                       • Updatable │ │                       • Signed Payload │ │                       • Can tag for emulation │ │      │ ├─UEFI Signature Database: │ │ │   Device ID:        0352a8acc949c7df21fec16e566ba9a74e797a97 │ │ │   Device Flags:     • Internal device │ │ │  │ │ ├─Oem Secure Boot DB 20231007: │ │ │     Device ID:      10e847d34a9f3fcbd55af51aa6a4262c2a74a9eb │ │ │     Current version: 2023 │ │ │     Vendor:         Unknown │ │ │     Update Error:   No vendor ID set │ │ │     GUID:           f5e4cf83-abd8-5826-95f6-eac517e19232 ← UEFI\CRT_0FD71FE7CC80435112F806DFDE5685E98D03D90A │ │ │     Device Flags:   • Internal device │ │ │                     • Needs a reboot after installation │ │ │                     • Updatable │ │ │                     • Signed Payload │ │ │                     • Can tag for emulation │ │ │    │ │ ├─Option ROM UEFI CA: │ │ │     Device ID:      92120fc1a625f725901333cbfec152b8d6e42d43 │ │ │     Current version: 2023 │ │ │     Vendor:         Microsoft (UEFI:Microsoft) │ │ │     GUIDs:          ca4668d9-734f-5b2b-aae8-8120b196f659 ← UEFI\VENDOR_Microsoft&NAME_Microsoft-Option-ROM-UEFI-CA │ │ │                     965d1919-0e18-5b63-9ebd-e5d122cd11df ← UEFI\CRT_F45B559FC1C60F31B3071021298D5ED7D77280B0 │ │ │     Device Flags:   • Internal device │ │ │                     • Updatable │ │ │                     • Needs a reboot after installation │ │ │                     • Signed Payload │ │ │                     • Can tag for emulation │ │ │    │ │ ├─UEFI CA: │ │ │     Device ID:      5bc922b7bd1adb5b6f99592611404036bd9f42d0 │ │ │     Current version: 2023 │ │ │     Vendor:         Microsoft (UEFI:Microsoft) │ │ │     GUIDs:          26f42cba-9bf6-5365-802b-e250eb757e96 ← UEFI\VENDOR_Microsoft&NAME_Microsoft-UEFI-CA │ │ │                     308281c7-d0c5-52e0-8c1a-810540de03df ← UEFI\CRT_7CD7437C555F89E7C2B50E21937E420C4E583E80 │ │ │     Device Flags:   • Internal device │ │ │                     • Updatable │ │ │                     • Supported on remote server │ │ │                     • Needs a reboot after installation │ │ │                     • Signed Payload │ │ │                     • Can tag for emulation │ │ │    │ │ └─Windows UEFI CA: │ │       Device ID:      d31da5f926c6d962ed810b284fab5a2ef623007b │ │       Current version: 2023 │ │       Vendor:         Microsoft (UEFI:Microsoft) │ │       GUIDs:          914015a8-9d92-5462-9a9b-f2b361e4faae ← UEFI\VENDOR_Microsoft&NAME_Windows-UEFI-CA │ │                       89a825bf-78b5-5f1c-905b-e982b2f02584 ← UEFI\CRT_A794240D25F0CCB2EC8142DC2F7411890717DEAD │ │       Device Flags:   • Internal device │ │                       • Updatable │ │                       • Needs a reboot after installation │ │                       • Signed Payload │ │                       • Can tag for emulation │ │      │ └─UEFI dbx: │       Device ID:        362301da643102b9f38477387e2193e57abaa590 │       Summary:          UEFI revocation database │       Current version:  20250507 │       Minimum Version:  20250507 │       Vendor:           UEFI:Microsoft │       Install Duration: 1 second │       Update Error:     System firmware cannot accept DBX updates │       GUIDs:            91aa5eb7-0f48-52ff-a68d-c01f25bc33a0 ← UEFI\CRT_9CD3A281B2EA0DE4E3D5FE17A9349C66A5256349FE36EF7A80A74051653443F0&ARCH_X64 │                         d07ff664-b0e1-5f4e-a723-d7fbcbfcb94f ← UEFI\CRT_3CD3F0309EDAE228767A976DD40D9F4AFFC4FBD5218F2E8CC3C9DD97E8AC6F9D&ARCH_X64 │                         f8ba2887-9411-5c36-9cee-88995bb39731 ← UEFI\CRT_A1117F516A32CEFCBA3F2D1ACE10A87972FD6BBE8FE0D0B996E09E65D802A503&ARCH_X64 │       Device Flags:     • Internal device │                         • Supported on remote server │                         • Needs a reboot after installation │                         • Device is usable for the duration of the update │                         • Updatable │                         • Only version upgrades are allowed │                         • Signed Payload │                         • Can tag for emulation │      └─TPM:       Device ID:          1d8d50a4dbc65618f5c399c2ae827b632b3ccc11       Current version:    600.18.0.1120       Vendor:             Intel (TPM:INTC)       GUIDs:              34801700-3a50-5b05-820c-fe14580e4c2d ← TPM\VEN_INTC&DEV_0000                           93532b61-86ce-57cf-8a31-f5a5553966c7 ← TPM\VEN_INTC&MOD_ADL                           03f304f4-223e-54f4-b2c1-c3cf3b5817c6 ← TPM\VEN_INTC&DEV_0000&VER_2.0                           12e61a33-eef7-58d6-855d-ece38114294d ← TPM\VEN_INTC&MOD_ADL&VER_2.0       Device Flags:       • Internal device                           • System requires external power source                           • Needs a reboot after installation                           • Device can recover flash failures                           • Signed Payload                           • Can tag for emulation      

Could you please check whether the DNN20 Backlight patch supports my serial number, or provide guidance / a matching patch for my unit? I can provide additional logs, BIOS/EC dumps, or tests if needed.

Thanks!

I am currently running Ubuntu 25.10 on mine and everything seems to be working ok. I am definitely no expert but maybe it is Fedora related? Have you tired running another distro? maybe through a Live USB? That might probably make the resolution easier for those that are more knowledgable about these things.

Perhaps it is Fedora related. Somewhere the firmware stopped working. I will load a live USB and check. I believe it not hardware related because the Caps Lock LED turns on, but the keyboard command to change keyboard backlight is not registering while others - such as changed screen brightness - do.

Edit: I tried it on a live CachyOS and Fedora 43 live USB. No luck. But that’s also understandable.

It is a firmware problem that Chuwi needs to look into - there are other similar posts here with the same problem.

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