Build OpenBMC with Yocto for the exact machine target, but do not treat flashing as a universal, one-command step. From the repository root, source the target setup and run bitbake obmc-phosphor-image. The resulting image, boot configuration, flash layout, update API and recovery procedure depend on the specific BMC and motherboard. Identify that hardware first, then use its vendor or platform instructions before writing anything to flash.
What OpenBMC is—and what this workflow does
OpenBMC is a customizable, open-source Linux firmware stack for Baseboard Management Controllers (BMCs) and related management controllers. It is built with the Yocto Project and OpenEmbedded, so a build is assembled for a declared hardware machine rather than produced as a generic image that fits every BMC.
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The repeatable part of the process is obtaining the source, selecting a supported machine configuration and running the image recipe. The hardware-specific part begins when you choose an artifact, decide how it is booted and update it. A target appearing in OpenBMC’s project list does not establish complete functionality, active maintenance, warranty coverage or reliable system-level behavior.
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Repair common Windows errors and clear accumulated junk for a smoother, more stable PC - no reinstall needed.Free scan · no reinstallThe project’s own compatibility question is essentially: “Will OpenBMC run on my Acme Server Corp. XYZ5000 motherboard?” The answer cannot be inferred from the fact that a similarly named board appears in a list. Confirm the exact board or BMC model, its flash device and its current firmware before building or updating.
#1 Best Overall
- Stable & Reliable CP2102 Chipset - Built with the trusted CP2102 chipset, ensuring stable data transmission and consistent performance. Supports 3.3V TTL logic level communication, making it suitable for most modern microcontroller systems.
- Extra Long 3ft/95cm Cable – More Flexible Than Standard Short Cables - Upgraded with a 3ft/95cm extended cable, providing greater flexibility than standard short cables. Perfect for hard-to-reach ports, complex setups and bench testing environments.
- Simplified 4-Wire Interface for Easy Wiring - Designed with a 4-pin configuration (TXD, RXD, VCC, GND), making connections faster, cleaner and less error-prone compared to traditional multi-pin modules.
- Plug and Play USB to TTL Adapter Cable - Easily connect TTL serial devices to your computer via USB without external power supply. Ideal for Arduino, ESP8266, ESP32, STM32 and other microcontroller platforms.
- Wide Compatibility for Development & Debugging - Provides stable 5V power output with 3.3V TTL signal level communication, ensuring reliable performance with Arduino, Raspberry Pi, ESP8266, ESP32 and other development boards.
Check the machine target and support level first
Find the exact target
Start with the motherboard or BMC’s full model and revision, not just the server family. Compare it with the machine names shown by the repository’s setup script and the project’s supported-machines documentation. The list describes targets for which support code has been contributed; it explicitly does not promise a known level of functionality, future development, bug fixes or a warranty.
Read the board’s platform notes as well as the machine name. Board support does not automatically mean that the complete server works. Cooling, for example, can depend on the BMC software, fan controllers, the chassis, fan wiring and system sensor configuration together.
For an unlisted board, porting is a separate engineering project. OpenBMC describes a new-platform port as non-trivial and says it is ideally done with manufacturer schematics and other documentation. Reverse engineering without documentation is possible but considerably harder and carries greater risk of hardware damage.
Use these two official references while checking compatibility:
- OpenBMC README — project targets, prerequisites and build overview.
- Supported machines — machine entries and their stated support caveats.
Record the information you will need for recovery
- Exact motherboard, BMC and board-revision identifiers.
- Current firmware version and a known-good backup, if the platform provides one.
- Flash part number, capacity and voltage.
- Boot-selector or recovery-jumper positions and any documented dual-image arrangement.
- Console connector, voltage level, pinout and baud rate.
- Vendor release notes and a documented way to recover from an interrupted update.
Do not assume that a USB-to-TTL adapter, SPI programmer or replacement flash chip is needed. Those are platform-dependent diagnostic or conversion tools. If a serial adapter is used, verify voltage, connector and pinout before connecting it.
Prepare a build host
The OpenBMC README gives example prerequisite packages for Ubuntu and Fedora and points to Yocto documentation for current host requirements. Package names and supported host versions can change as the project and Yocto release move, so check the current documentation when provisioning the machine rather than treating an old package list as timeless.
Rank #2
- Support 4 kinds of TTL levels:This is a versatile USB to TTL converter. It is powerful enough to handle almost all TTL level communications. It is compatible with 5V, 3.3V, 2.5V, 1.8V TTL levels.
- FTDI FT232RNL Chip:Built-in original FTDI FT232RNL Chip.Industrial grade, Compatible with Windows 7, 8, 10, 11, Linux, MacOS
- Protective case:Comes with a protective case, this transparent protective case can effectively prevent static interference from the hand and prevent accidental short circuit
- It provides access not only to UART TX,RX, RTS, CTS, VCC and GND pins,but also provides access to DSR,RI,DCD,DTR,RESET pins
- What You Get: SH-U09C5 USB to UART Adatper, 6PIN Cable
A practical preparation checklist is:
- Use a supported 64-bit Linux host with enough disk space for Yocto downloads, shared state and build output.
- Install the prerequisite packages for your distribution from the current README.
- Ensure the host can reach the source and download mirrors used by the build.
- Plan for long compile times and substantial temporary storage; the project does not publish a universal build-time estimate.
- Keep the build directory on a filesystem with adequate free space and normal file permissions.
For current host guidance and the OpenBMC-specific Yocto workflow, consult Yocto in OpenBMC.
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1Clear out junk files and repair common Windows errors2Scan for outdated or missing drivers - takes under a minute3Repair Windows errors before they cause bigger problemsBuild an OpenBMC image step by step
1. Clone the source
Run the documented commands on the build host:
git clone https://github.com/openbmc/openbmc
cd openbmcThese commands place you in the repository root. The setup script must be sourced from this directory.
2. Select the machine configuration
To see the machine targets known to the checkout, run:
. setupWith no arguments, setup displays supported hardware targets. Select the entry that corresponds to the exact board or BMC, then source setup with that machine name:
. setup <machine> [build_dir]Replace <machine> with the target name. The optional build_dir lets you place the build output in a named directory; omitting it uses the project’s normal default. Because this command sets the build environment in your current shell, the leading dot and space matter.
Do not substitute a nearby or similarly named machine merely to make the build proceed. A successful compilation for the wrong target can still produce an image that has the wrong device tree, boot settings, drivers or flash assumptions.
Rank #3
- Stable and reliable chipset CP2102
- Baud rates: 300 bps to 1.5 Mbps
- Connect MCU easily to your computer!
- Standard USB type A male and TTL 5pin connector. 5pins for 3.3V, RST, TXD, RXD, GND & 5V
- Supports Windows 98SE, 2000, XP, Vista, Window7, Mac OS 9, Mac OS X & Linux 2.40
3. Build the standard image
The official README’s example image target is:
bitbake obmc-phosphor-imageYocto resolves recipes, layers and machine settings, then writes artifacts under the configured build directory. Exact filenames, formats and paths vary with the machine configuration and the revision you checked out. Treat the generated files as build outputs to be matched against the selected platform’s update instructions, not as interchangeable raw flash dumps.
4. Locate and identify the artifacts
After BitBake completes, inspect the machine-specific deploy directory and identify which file the platform documentation calls for. Names such as image-bmc can occur, but the exact artifact and packaging depend on the target. Check:
- Whether the file is a complete update package, a bootable image, a partition image or another format.
- Whether checksums or signatures are supplied and how the BMC verifies them.
- Which flash offset, partition or update endpoint the platform expects.
- Whether the image is for a primary or alternate bank.
Never infer those properties from the filename alone.
5. Customize only when needed
A basic build does not require recipe changes. For development work, the OpenBMC Yocto guide documents devtool for adding or editing recipes and changing what is installed in an image. Keep customizations separate from the first hardware-validation build so that a failure can be attributed to the platform configuration rather than an untested recipe modification.
Why flashing cannot have one universal command
OpenBMC’s flash-layout documentation describes several implementation choices: boot selection, partition boundaries, writable overlays, filesystem types and update behavior. U-Boot initializes the system, while examples include a read-only SquashFS root with writable storage elsewhere. These choices determine whether an update is performed through a management API, a bootloader environment, a vendor utility, an external programmer or a board-specific script.
Consequently, do not publish or execute a raw SPI-writing command for an unidentified BMC. The wrong offset, image type or bank can leave the controller unbootable, overwrite recovery data or damage hardware. The selected machine’s documentation must define the image format, write method, boot configuration and recovery sequence.
Rank #4
- Stable & Trusted CP2102 Chipset – Built with the reliable CP2102 chipset for stable data transmission and consistent performance in embedded and serial communication projects.
- Flexible Baud Rate Range – Supports a wide range of baud rates from 300 bps to 1.5 Mbps, meeting various data transmission needs for microcontrollers and development boards.
- Plug-and-Play USB Connectivity – Easily connects your TTL serial devices to a computer via USB. No external power supply needed. Ideal for Arduino, ESP8266, STM32, STC, and more.
- Standard Pin Configuration – Features USB Type-A male and TTL 5-pin female header (3.3V, RST, TXD, RXD, GND). Compatible with both 3.3V and 5V logic levels, ensuring broader hardware support.
- Broad OS Compatibility – Works with Windows 98SE/2000/XP/Vista/7/10/11, Mac OS 9/X, and Linux 2.4+, making it a versatile solution for developers and DIY electronics enthusiasts.
Read OpenBMC Flash Layout and Filesystem Documentation alongside the board’s own instructions to understand why two OpenBMC systems may require different update procedures.
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| Route | What must be established first | Typical dependencies and risks |
|---|---|---|
| Platform-approved Redfish update | The live service exposes an UpdateService and an applicable image-upload mechanism. | Requires network access, authentication and implementation-specific ApplyTime, validation and reboot behavior. |
| Vendor or board utility | The utility and image package are documented for the exact model and firmware generation. | May require a local operating system, a management interface or a particular boot mode. |
| Bootloader or local console procedure | Exact U-Boot variables, partitions, console settings and recovery steps are known. | Usually needs physical access; a wrong command can overwrite the boot or recovery area. |
| External SPI programming | The flash part, voltage, clip or socket, image layout and backup process are confirmed. | Requires hardware access and careful power isolation; it is not a generic OpenBMC installation method. |
Compare routes on the exact board’s support maturity, image format, physical-access requirement, rollback or multiple-image capability, and the availability of schematics and recovery documentation. They are not interchangeable simply because they all carry an OpenBMC-derived image.
Redfish firmware update: a conditional path
Where implemented, Redfish can provide a network update path. OpenBMC’s design describes this conceptual HTTP-push sequence:
- Request
/redfish/v1/UpdateService. - Inspect the returned service for an advertised
HttpPushUri. - If the implementation exposes it, choose an appropriate
ApplyTimevalue according to the service’s rules. - POST the image to the advertised URI and monitor the task or update status.
The endpoint, authentication requirements, accepted image package and reboot behavior must be read from the live service and platform documentation. The design document is an explanation of an implementation path, not proof that every current OpenBMC machine supports those exact properties.
The same document describes a SimpleUpdate example using TFTP. TFTP has no transport security, and the described bmcweb support is configurable and disabled by default. Do not enable or use it on the assumption that it is present or safe; use an authenticated, platform-approved route instead.
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See Firmware update over Redfish for the design details and limitations.
Best Value
- 6 ft USB to TTL serial adapter (with 4 pin 0.1” pitch female header socket) connects devices with 3.3 V logic level UART signals interface to a laptop via USB port
- A genuine PL2303TA chip module is housed in USB 2.0 type A male terminal for wider compatibility and supports reliable data transfer rates
- 6 feet USB to TTL serial cable 3V3 (4 way output flying leads ) provides access to UART (transmit) Tx, (receive) Rx, VCC (5V) and GND
- PL2303 Prolific chipset on the PCB board has configurable internal EEPROM and UART signals can be individually inverted by configuring the EEPROM
- 4 pin 3.3V USB to TTL converter cord Compatible with Windows 10, 8, 8.1, 7 (32, 64-bit), 2008/XP/Vista/CE; ideal USB 2.0 debug cord for Vendor ID re-write, router, GPS, set top box, transmitter, flash firmware on hard drive, etc.
Pre-flash safety checks
Before starting any update method, complete these checks for the specific machine:
- Confirm that the image was built for the exact machine target and hardware revision.
- Confirm the expected image format, partition or endpoint and the platform’s image-verification rules.
- Save the current firmware and configuration if the vendor procedure supports backup.
- Provide stable power to the server and the BMC; avoid planned power interruptions during erase, write or reboot stages.
- Have the documented recovery path ready before you begin, including console, jumper, alternate bank or external programmer requirements.
- Arrange physical access if the update can disable network management or requires a recovery action.
- Record the original boot settings so they can be restored if the update changes them.
If any of these details are unknown, stop and obtain the board-specific documentation. A completed BitBake build is not evidence that the resulting file is safe to flash.
Board-specific example: converting a Palmetto system
OpenBMC’s AMI-to-OpenBMC conversion notes illustrate why a concrete procedure must not be generalized. For the Palmetto platform, the notes call for upgrading the flash to a 256 Mbit (32 MB) device, such as an MX25L25635E or equivalent, then building and flashing the image-bmc output. The conversion also involves replacing the motherboard flash chip and connecting a COM2 console cable.
That console uses a DB-9-style pinout and runs at 115200 baud. Those flash capacity, chip, console and replacement steps belong to the Palmetto conversion procedure; they are not normal requirements for every BMC or every OpenBMC machine.
Use the complete platform notes at Converting to OpenBMC from AMI firmware, and verify that the hardware revision and electrical details match before handling the board.
Troubleshooting by symptom
The setup command does not list the board
- Confirm you are in the repository root and sourced the script with
. setup. - Check the current supported-machine documentation and the exact board identifier.
- Do not pick a similarly named target as a workaround; investigate whether a port or vendor-maintained layer exists.
BitBake fails before compiling
- Recheck the current Ubuntu or Fedora prerequisites in the README and Yocto host requirements.
- Verify network access to source mirrors and sufficient disk space.
- Capture the first meaningful error rather than repeatedly rerunning after later cascade errors.
- Keep the machine configuration fixed while diagnosing so that changing targets does not hide the cause.
The image builds but the BMC does not boot
- Reconfirm the machine target, image artifact and hardware revision.
- Check boot-selector settings, partition layout and whether the platform expects a signed or packaged update.
- Connect the documented console at the correct voltage and baud rate, if available.
- Use the approved recovery path instead of repeatedly erasing or rewriting unknown offsets.
A Redfish upload is unavailable or rejected
- Query the live
/redfish/v1/UpdateServiceresource and check whether anHttpPushUriis advertised. - Verify authentication, accepted media type, image compatibility and any required ApplyTime property.
- Follow the platform’s local or vendor-specific update method when the service does not expose the needed capability.
A repeatable decision process
- Identify: record the exact BMC, motherboard, revision and current firmware.
- Match: select the corresponding OpenBMC machine target and read its support caveats.
- Build: clone the repository, source
. setup <machine> [build_dir]and runbitbake obmc-phosphor-image. - Map: match the generated artifact to the platform’s documented format, partitioning and verification method.
- Choose: use only an update route the platform documents—Redfish, a vendor utility, a local bootloader procedure or approved programming hardware.
- Recover: keep stable power, console or physical access and a tested recovery plan available through the reboot.
- Validate: after the update, verify boot, network management, sensors, fan control and the system functions that matter for that server.
This process separates what is reproducible across OpenBMC builds from what must be decided for one piece of hardware. The source build is standardized; image installation is not.
Quick Recap
Official references
- OpenBMC README
- Yocto in OpenBMC
- Supported machines
- Flash Layout and Filesystem Documentation
- Firmware update over Redfish
- Converting to OpenBMC from AMI firmware
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