Debugging

Similar to other projects working with hardware OpenCore supports auditing and debugging. The use of NOOPT or DEBUG build modes instead of RELEASE can produce a lot more debug output. With NOOPT source level debugging with GDB or IDA Pro is also available. For GDB check OpenCore Debug page. For IDA Pro, version 7.3 or newer is needed, and Debugging the XNU Kernel with IDA Pro may also help.

To obtain the log during boot serial port debugging can be used. Serial port debugging is enabled in Target, e.g. 0xB for onscreen with serial. To initialise serial within OpenCore use Init configuration option under Misc->Serial with other values properly set. For macOS the best choice is CP2102-based UART devices. Connect motherboard TX to USB UART RX, and motherboard GND to USB UART GND. Use screen utility to get the output, or download GUI software, such as CoolTerm.

Note: On several motherboards (and possibly USB UART dongles) PIN naming may be incorrect. It is very common to have GND swapped with RX, thus, motherboard “TX” must be connected to USB UART GND, and motherboard “GND” to USB UART RX.

Remember to enable COM port in firmware settings, and never use USB cables longer than 1 meter to avoid output corruption. To additionally enable XNU kernel serial output debug=0x8 boot argument is needed.