sousana96115c602f0
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- Apr 30, 2026
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Hi everyone, I'm hoping someone here has seen this before because I'm running out of ideas.
I have an MPG B550 Gaming Plus (MS-7C56) that's about a year old. At some point Mystic Light started showing "The mainboard's LED firmware is abnormal", and any ARGB device I plug into JRAINBOW headers is just never detected by MSI Center. So I downloaded the 7C56 LED firmware update tool from the MSI support page, ran it as admin, and it always tells me "Connect to device fail". I've been trying to fix this for a while and nothing works.
What I've tried so far: I reinstalled MSI Center and Mystic Light from scratch several times. I updated the BIOS to v1.K0 which is the latest. I checked that the MSI services are actually running. I scanned for MSI HID and USB devices through PowerShell, Device Manager and PnP enumeration and there's no MSI LED HID device showing up at all, no relevant VID_1462 entry. I unplugged the ARGB hub completely from JRAINBOW2 in case it was interfering. I did a Clear CMOS with the jumper. I switched LED_SW1 to OFF and rebooted, no new device appears either way. I read somewhere that shorting JT1 might trigger a recovery mode, tried it, no change. I did a full cold reset, PSU off at the switch, power cable out, power button held for 30 seconds, waited 5 minutes, plugged everything back. After every single one of these steps I tried the firmware tool again, always the same "Connect to device fail".
Someone suggested the LED controller talks over SMBus rather than USB, so I tried checking from Ubuntu to bypass any Windows software issue. I installed i2c-tools and ran i2cdetect on the three SMBus PIIX4 buses the board exposes. I can see my RAM SPDs at 0x52 and 0x53 so the scan definitely works, but nothing responds at 0x4D, 0x4E or 0x4F where the Nuvoton LED chip is supposed to sit, on any of the three buses. lspci confirms the SMBus controller is fine and the piix4_smbus driver is loaded with the MSI subsystem ID. dmesg has no errors. lsusb shows no MSI device anywhere. OpenRGB doesn't see anything either, on Windows or on Linux.
So from what I can tell the chip just isn't talking on the bus anymore, which would explain why the firmware tool can't connect, but I don't know what to do with that information. I haven't done anything weird to the board, no overclocking, no flashing accidents that I'm aware of. It just stopped working. Is there any way to wake the chip back up? Some kind of hardware-level reset I haven't tried? A specific JT1 procedure with timing I'm missing? Is there a different firmware tool somewhere that I should be using instead of the one on the support page? Has anyone managed to recover from this state without RMA?
I'm a bit stuck and would really appreciate any pointers. Thanks for reading.
I have an MPG B550 Gaming Plus (MS-7C56) that's about a year old. At some point Mystic Light started showing "The mainboard's LED firmware is abnormal", and any ARGB device I plug into JRAINBOW headers is just never detected by MSI Center. So I downloaded the 7C56 LED firmware update tool from the MSI support page, ran it as admin, and it always tells me "Connect to device fail". I've been trying to fix this for a while and nothing works.
What I've tried so far: I reinstalled MSI Center and Mystic Light from scratch several times. I updated the BIOS to v1.K0 which is the latest. I checked that the MSI services are actually running. I scanned for MSI HID and USB devices through PowerShell, Device Manager and PnP enumeration and there's no MSI LED HID device showing up at all, no relevant VID_1462 entry. I unplugged the ARGB hub completely from JRAINBOW2 in case it was interfering. I did a Clear CMOS with the jumper. I switched LED_SW1 to OFF and rebooted, no new device appears either way. I read somewhere that shorting JT1 might trigger a recovery mode, tried it, no change. I did a full cold reset, PSU off at the switch, power cable out, power button held for 30 seconds, waited 5 minutes, plugged everything back. After every single one of these steps I tried the firmware tool again, always the same "Connect to device fail".
Someone suggested the LED controller talks over SMBus rather than USB, so I tried checking from Ubuntu to bypass any Windows software issue. I installed i2c-tools and ran i2cdetect on the three SMBus PIIX4 buses the board exposes. I can see my RAM SPDs at 0x52 and 0x53 so the scan definitely works, but nothing responds at 0x4D, 0x4E or 0x4F where the Nuvoton LED chip is supposed to sit, on any of the three buses. lspci confirms the SMBus controller is fine and the piix4_smbus driver is loaded with the MSI subsystem ID. dmesg has no errors. lsusb shows no MSI device anywhere. OpenRGB doesn't see anything either, on Windows or on Linux.
So from what I can tell the chip just isn't talking on the bus anymore, which would explain why the firmware tool can't connect, but I don't know what to do with that information. I haven't done anything weird to the board, no overclocking, no flashing accidents that I'm aware of. It just stopped working. Is there any way to wake the chip back up? Some kind of hardware-level reset I haven't tried? A specific JT1 procedure with timing I'm missing? Is there a different firmware tool somewhere that I should be using instead of the one on the support page? Has anyone managed to recover from this state without RMA?
I'm a bit stuck and would really appreciate any pointers. Thanks for reading.
