CEC10 Frequently Asked Questions (FAQ)

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Question #424: I have a MPL SBC with "Secure Boot" enabled. I have also installed a "Secure Boot" capable OS some time ago and all was working fine so far. Now I updated the BIOS of the SBC and since the update, the OS does not boot any longer. What's wrong?
Answer: Does the PCN for the new BIOS mention an "Update to the Secure Boot Keys" or similar?
In this case the BIOS update most probably has installed some new "revoked" keys into the list of known "forbidden" keys maintained by the BIOS.
Unfortunately your installed OS seems to use one of this "forbidden" key, resulting in a non-bootable OS.
As this is NOT primarily a problem of the MPL SBC, but rather a problem of the used OS, please check with the manufacturer/vendor of OS how to fix this issue.
Please note that a BIOS update is NOT the only way for a new "revoked" key to be inserted into your system. The same can be triggered by an ordinary OS update or even manually as well.

Question #426: I'm facing the problem that an external monitor seems to be detected only at boot time by your SBC.
If I connect it after the SBC has booted, the system does not seem to detect its presence.
Answer: Is the monitor connected to a video output implemented using eDP?
If yes, than the above is the correct behaviour.
Please note that eDP scans for possible output devices only once during system start-up. Any changes in system configuration or device state afterwards are simply ignored.

Question #422: I observe sudden, unmotivated reboots of my CEC1x SBC. The behaviour is pretty erratic. I already replace the memory module, but without success.
Answer: Please check the Power Management Controller (PMC) firmware version of your SBC as described in the CEC10 System BIOS User Manual. In case the PMC firmare version is lower than 29, please update it using this Update package.
To update the PMC firmware, please follow the instructions mentioned in the PDF inside the ZIP archive.

Question #418: Can the HSUART ports on the CEC1x be used for RS232, RS485 and RS422?
Answer: Due to hardware limitations ("autoRTS" feature not available) on the HSUART controller, only RS232 and RS422 modes are supported.

Question #417: Under Linux, I don't find a driver for the HSUARTs on the CEC1x?
Answer: A suitable driver for the LPSS HSUARTs is part of the Linux kernel source since (at least) version 4.9.
Unfortunatly some distro kernel do not include this driver by default in their standard kernel builds.
Therefore you may have to build your own kernel. Please make sure that the "CONFIG_SERIAL_8250_LPSS" kernel build option is active.

Question #401: If there are two (or more) drives connected to the SATA ports of your SBC, Windows [7|8|10] is normally labeling the drive connected to SATA0 as "Disk 0" and the drive connected to SATA1 as "Disk 1".
But sometimes it's just the other way around!

Answer: This is a Windows "feature" as explained here: Disk drive numbers may not correspond to the SATA channel numbers

Question #325: How can I reset the BIOS settings to factory defaults?
Answer: There is a special menu entry in the BIOS setup screen, which will reset all BIOS settings to their factory defaults.
If entering the BIOS setup screen is not possible, the recommended way is to switch off the CMOS backup power (either by removing the CMOS battery completely from its holder or by using the corresponding DIP switch as described in the product "User Manual"). That way, the BIOS settings are gone and the default ones are loaded at next system boot. After the system has booted successfully, don't forget to connect/switch on the CMOS backup power again.

Question #247: My MPL SBC does not [boot|start] up. What can I do?
Answer: First of all, what precisely is meant by "does not [boot|start] up"?

Is the system not powering up at all or is there some reaction / output from the BIOS/bootloader, but no operating system is loaded or started?

If it is the former, please do the following:
  • check the status indicators (LEDs) if any.
  • press the power button if available.
  • check the power supply, cabling and fuse.
If it is the latter, please do the following:
  • try to boot the system from a known good bootable media (CD/DVD, USB, network, ...).
  • check the integrity and status of the default boot media. Replace the boot media if necessary.
  • if the software and/or hardware has been changed recently, retract the change(s).
  • recover the system from a backup.

Please note that the above is just a rough list of things to check and try. Please use the corresponding manual for detailed information and precise instructions for a particular MPL product.

Question #228: I observe power-up problems or sudden, unmotivated resets of the MPL SBC during normal operation. It seems to get worse if an additional add-on card is installed and/or the CPU and/or GPU load is increased.
Answer: Sounds like the external power supply is unable to sustain the highly dynamic power requirements of most modern CPUs.
  • Have you checked that the power supply is suitable for the SBC? Please check the corresponding documentation for details on the power requirements of the SBC in question.
  • Have you tried another, more powerful power supply yet?

Question #248: The RESET LED is blinking. What's wrong?
Answer: This means that the internal power supply of the SBC has detected an overload or even short-circuit condition on one of its power rails.

Please follow the steps below:
  • Disconnect the power, wait 10 seconds, then reconnect the power again.
  • If this doesn't help, disconnect the power, remove all cables and/or add-on cards (especially the ones which may have been recently installed or changed) except the power cord and reconnect the power again.
  • If there is no blinking RESET LED, try to isolate the culprit by reconnecting / reinstalling all the previously disconnected / removed items one after the other.
  • If the problem persists, the system needs most probably to be returned to MPL for a detailed analysis.

Question #351: Since I updated to Linux Kernel 2.6.30 or higher, all I2C peripherals (like temperature sensors or EEPROM) are not working any longer. With an older kernel, everything is working fine.
Answer: Is there a message similar to:
  • "ACPI: I/O resource ... conflicts with ACPI region SMB0"
  • "ACPI Warning: SystemIO range ... conflicts with OpRegion ... (\_SB.PCI0.SBUS.SMBI) "
 present in the kernel log?

If yes, please add "acpi_enforce_resources=lax" to the kernel command line.
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