I successfully booted my IMB-A180 using the latest sources from coreboot.org. It would be helpful to know which variant of the ASRock board you have. The information is located on a sticker near the 20-pin power connector.
Try the following .config file but make sure that the video device matches your board and the VBIOS location matches your development system:
#
# Automatically generated make config: don't edit
# coreboot version: 4.0-4832-gcae09e0
# Mon Nov 25 11:18:41 2013
#
#
# General setup
#
CONFIG_EXPERT=y
CONFIG_LOCALVERSION="Open-source BIOS for ASRock IMB-A180"
CONFIG_CBFS_PREFIX="fallback"
# CONFIG_ALT_CBFS_LOAD_PAYLOAD is not set
CONFIG_COMPILER_GCC=y
# CONFIG_COMPILER_LLVM_CLANG is not set
# CONFIG_SCANBUILD_ENABLE is not set
# CONFIG_CCACHE is not set
# CONFIG_SCONFIG_GENPARSER is not set
# CONFIG_USE_OPTION_TABLE is not set
CONFIG_COMPRESS_RAMSTAGE=y
CONFIG_INCLUDE_CONFIG_FILE=y
# CONFIG_EARLY_CBMEM_INIT is not set
# CONFIG_DYNAMIC_CBMEM is not set
# CONFIG_COLLECT_TIMESTAMPS is not set
CONFIG_USE_BLOBS=y
# CONFIG_COVERAGE is not set
#
# Mainboard
#
# CONFIG_VENDOR_AAEON is not set
# CONFIG_VENDOR_ABIT is not set
# CONFIG_VENDOR_ADLINK is not set
# CONFIG_VENDOR_ADVANSUS is not set
# CONFIG_VENDOR_ADVANTECH is not set
# CONFIG_VENDOR_AMD is not set
# CONFIG_VENDOR_AOPEN is not set
# CONFIG_VENDOR_ARIMA is not set
# CONFIG_VENDOR_ARTECGROUP is not set
# CONFIG_VENDOR_ASI is not set
CONFIG_VENDOR_ASROCK=y
# CONFIG_VENDOR_ASUS is not set
# CONFIG_VENDOR_A_TREND is not set
# CONFIG_VENDOR_AVALUE is not set
# CONFIG_VENDOR_AXUS is not set
# CONFIG_VENDOR_AZZA is not set
# CONFIG_VENDOR_BACHMANN is not set
# CONFIG_VENDOR_BCOM is not set
# CONFIG_VENDOR_BIFFEROS is not set
# CONFIG_VENDOR_BIOSTAR is not set
# CONFIG_VENDOR_BROADCOM is not set
# CONFIG_VENDOR_COMPAQ is not set
# CONFIG_VENDOR_DIGITALLOGIC is not set
# CONFIG_VENDOR_DMP is not set
# CONFIG_VENDOR_EAGLELION is not set
# CONFIG_VENDOR_ECS is not set
# CONFIG_VENDOR_EMULATION is not set
# CONFIG_VENDOR_GETAC is not set
# CONFIG_VENDOR_GIGABYTE is not set
# CONFIG_VENDOR_GOOGLE is not set
# CONFIG_VENDOR_HP is not set
# CONFIG_VENDOR_IBASE is not set
# CONFIG_VENDOR_IBM is not set
# CONFIG_VENDOR_IEI is not set
# CONFIG_VENDOR_INTEL is not set
# CONFIG_VENDOR_IWAVE is not set
# CONFIG_VENDOR_IWILL is not set
# CONFIG_VENDOR_JETWAY is not set
# CONFIG_VENDOR_KONTRON is not set
# CONFIG_VENDOR_LANNER is not set
# CONFIG_VENDOR_LENOVO is not set
# CONFIG_VENDOR_LIPPERT is not set
# CONFIG_VENDOR_MITAC is not set
# CONFIG_VENDOR_MSI is not set
# CONFIG_VENDOR_NEC is not set
# CONFIG_VENDOR_NEWISYS is not set
# CONFIG_VENDOR_NOKIA is not set
# CONFIG_VENDOR_NVIDIA is not set
# CONFIG_VENDOR_PCENGINES is not set
# CONFIG_VENDOR_RCA is not set
# CONFIG_VENDOR_RODA is not set
# CONFIG_VENDOR_SAMSUNG is not set
# CONFIG_VENDOR_SIEMENS is not set
# CONFIG_VENDOR_SOYO is not set
# CONFIG_VENDOR_SUNW is not set
# CONFIG_VENDOR_SUPERMICRO is not set
# CONFIG_VENDOR_TECHNEXION is not set
# CONFIG_VENDOR_TECHNOLOGIC is not set
# CONFIG_VENDOR_TELEVIDEO is not set
# CONFIG_VENDOR_TI is not set
# CONFIG_VENDOR_THOMSON is not set
# CONFIG_VENDOR_TRAVERSE is not set
# CONFIG_VENDOR_TYAN is not set
# CONFIG_VENDOR_VIA is not set
# CONFIG_VENDOR_WINENT is not set
# CONFIG_VENDOR_WYSE is not set
CONFIG_BOARD_SPECIFIC_OPTIONS=y
CONFIG_MAINBOARD_DIR="asrock/imb-a180"
CONFIG_MAINBOARD_PART_NUMBER="IMB-A180"
CONFIG_IRQ_SLOT_COUNT=11
CONFIG_MAINBOARD_VENDOR="ASROCK"
CONFIG_APIC_ID_OFFSET=0x0
CONFIG_HW_MEM_HOLE_SIZEK=0x200000
CONFIG_MAX_CPUS=4
CONFIG_MAX_PHYSICAL_CPUS=1
# CONFIG_HW_MEM_HOLE_SIZE_AUTO_INC is not set
CONFIG_MEM_TRAIN_SEQ=2
CONFIG_RAMTOP=0x1000000
CONFIG_HEAP_SIZE=0xc0000
CONFIG_RAMBASE=0x200000
CONFIG_VGA_BIOS_ID="1002,9834"
CONFIG_DRIVERS_PS2_KEYBOARD=y
CONFIG_ONBOARD_VGA_IS_PRIMARY=y
CONFIG_VGA_BIOS=y
# CONFIG_CONSOLE_POST is not set
# CONFIG_PCI_ROM_RUN is not set
# CONFIG_UDELAY_IO is not set
CONFIG_DCACHE_RAM_BASE=0x30000
CONFIG_DCACHE_RAM_SIZE=0x10000
CONFIG_SERIAL_CPU_INIT=y
CONFIG_ACPI_SSDTX_NUM=0
CONFIG_VGA_BIOS_FILE="site-local/1407514.002"
# CONFIG_HUDSON_LEGACY_FREE is not set
# CONFIG_BOARD_ASROCK_939A785GMH is not set
# CONFIG_BOARD_ASROCK_E350M1 is not set
CONFIG_BOARD_ASROCK_IMB_A180=y
CONFIG_AZ_PIN=0x2
# CONFIG_PCI_64BIT_PREF_MEM is not set
CONFIG_MMCONF_BASE_ADDRESS=0xA0000000
CONFIG_ID_SECTION_OFFSET=0x80
CONFIG_XIP_ROM_SIZE=0x100000
# CONFIG_MMCONF_SUPPORT_DEFAULT is not set
CONFIG_MAINBOARD_SMBIOS_MANUFACTURER="ASROCK"
CONFIG_SEABIOS_PS2_TIMEOUT=0
# CONFIG_POWER_BUTTON_FORCE_ENABLE is not set
CONFIG_LOGICAL_CPUS=y
CONFIG_IOAPIC=y
CONFIG_SMP=y
CONFIG_TTYS0_BAUD=115200
CONFIG_TTYS0_BASE=0x3f8
CONFIG_TTYS0_LCS=3
CONFIG_DEFAULT_CONSOLE_LOGLEVEL=5
CONFIG_CONSOLE_SERIAL8250=y
# CONFIG_USBDEBUG is not set
# CONFIG_K8_REV_F_SUPPORT is not set
CONFIG_CPU_ADDR_BITS=40
CONFIG_BOARD_ROMSIZE_KB_4096=y
# CONFIG_COREBOOT_ROMSIZE_KB_64 is not set
# CONFIG_COREBOOT_ROMSIZE_KB_128 is not set
# CONFIG_COREBOOT_ROMSIZE_KB_256 is not set
# CONFIG_COREBOOT_ROMSIZE_KB_512 is not set
# CONFIG_COREBOOT_ROMSIZE_KB_1024 is not set
# CONFIG_COREBOOT_ROMSIZE_KB_2048 is not set
CONFIG_COREBOOT_ROMSIZE_KB_4096=y
# CONFIG_COREBOOT_ROMSIZE_KB_8192 is not set
# CONFIG_COREBOOT_ROMSIZE_KB_16384 is not set
CONFIG_COREBOOT_ROMSIZE_KB=4096
CONFIG_ROM_SIZE=0x400000
CONFIG_MAINBOARD_SERIAL_NUMBER="IMB-A180"
CONFIG_MAINBOARD_VERSION="1.0"
CONFIG_MAINBOARD_SMBIOS_PRODUCT_NAME="IMB-A180"
CONFIG_ARCH_X86=y
# CONFIG_ARCH_ARMV7 is not set
#
# Architecture (x86)
#
CONFIG_X86_ARCH_OPTIONS=y
# CONFIG_MARK_GRAPHICS_MEM_WRCOMB is not set
# CONFIG_AP_IN_SIPI_WAIT is not set
# CONFIG_SIPI_VECTOR_IN_ROM is not set
CONFIG_STACK_SIZE=0x1000
CONFIG_MAX_REBOOT_CNT=3
CONFIG_NUM_IPI_STARTS=2
CONFIG_X86_BOOTBLOCK_SIMPLE=y
# CONFIG_X86_BOOTBLOCK_NORMAL is not set
CONFIG_BOOTBLOCK_SOURCE="bootblock_simple.c"
# CONFIG_UPDATE_IMAGE is not set
# CONFIG_ROMCC is not set
CONFIG_PC80_SYSTEM=y
# CONFIG_HAVE_CMOS_DEFAULT is not set
CONFIG_BOOTBLOCK_SOUTHBRIDGE_INIT="southbridge/amd/agesa/hudson/bootblock.c"
CONFIG_IOAPIC_INTERRUPTS_ON_FSB=y
# CONFIG_IOAPIC_INTERRUPTS_ON_APIC_SERIAL_BUS is not set
CONFIG_HPET_ADDRESS=0xfed00000
CONFIG_HAVE_ARCH_MEMSET=y
CONFIG_HAVE_ARCH_MEMCPY=y
CONFIG_HAVE_ARCH_MEMMOVE=y
#
# Chipset
#
#
# CPU
#
CONFIG_CPU_SOCKET_TYPE=0x10
# CONFIG_EXT_RT_TBL_SUPPORT is not set
# CONFIG_EXT_CONF_SUPPORT is not set
CONFIG_CBB=0x0
CONFIG_CDB=0x18
CONFIG_DIMM_SUPPORT=0x0104
CONFIG_LIFT_BSP_APIC_ID=y
CONFIG_UDELAY_LAPIC_FIXED_FSB=200
CONFIG_CPU_AMD_AGESA=y
CONFIG_HAVE_INIT_TIMER=y
CONFIG_HIGH_SCRATCH_MEMORY_SIZE=0xA1000
CONFIG_CPU_AMD_AGESA_FAMILY16_KB=y
CONFIG_XIP_ROM_BASE=0xfff80000
CONFIG_SMM_TSEG_SIZE=0
# CONFIG_SSE2 is not set
# CONFIG_CPU_INTEL_FIRMWARE_INTERFACE_TABLE is not set
CONFIG_UDELAY_LAPIC=y
CONFIG_LAPIC_MONOTONIC_TIMER=y
# CONFIG_UDELAY_TSC is not set
# CONFIG_UDELAY_TIMER2 is not set
# CONFIG_TSC_CALIBRATE_WITH_IO is not set
CONFIG_TSC_SYNC_LFENCE=y
# CONFIG_TSC_SYNC_MFENCE is not set
# CONFIG_CACHE_ROM is not set
# CONFIG_SMM_TSEG is not set
CONFIG_X86_AMD_FIXED_MTRRS=y
CONFIG_CACHE_AS_RAM=y
CONFIG_AP_SIPI_VECTOR=0xfffff000
# CONFIG_CPU_MICROCODE_IN_CBFS is not set
# CONFIG_CPU_MICROCODE_CBFS_GENERATE is not set
# CONFIG_CPU_MICROCODE_CBFS_EXTERNAL is not set
CONFIG_CPU_MICROCODE_CBFS_NONE=y
#
# Northbridge
#
CONFIG_SB_HT_CHAIN_UNITID_OFFSET_ONLY=y
CONFIG_VIDEO_MB=0
CONFIG_AMDMCT=y
CONFIG_MMCONF_BUS_NUMBER=256
CONFIG_NORTHBRIDGE_AMD_AGESA=y
# CONFIG_CONSOLE_VGA_MULTI is not set
# CONFIG_S3_VGA_ROM_RUN is not set
CONFIG_NORTHBRIDGE_AMD_AGESA_FAMILY16_KB=y
# CONFIG_AMD_NB_CIMX is not set
# CONFIG_NORTHBRIDGE_AMD_CIMX_RD890 is not set
CONFIG_CBFS_SIZE=0x400000
CONFIG_MAX_PIRQ_LINKS=4
#
# Southbridge
#
CONFIG_EHCI_BAR=0xfef00000
CONFIG_EHCI_DEBUG_OFFSET=0xe0
# CONFIG_AMD_SB_CIMX is not set
CONFIG_S3_DATA_POS=0xFFFF0000
CONFIG_S3_DATA_SIZE=32768
# CONFIG_SOUTHBRIDGE_AMD_CIMX_SB800 is not set
CONFIG_AHCI_ROM_ID="1022,7801"
# CONFIG_SOUTHBRIDGE_AMD_CIMX_SB900 is not set
CONFIG_SOUTHBRIDGE_AMD_AGESA_YANGTZE=y
# CONFIG_SOUTHBRIDGE_AMD_HUDSON_SKIP_ISA_DMA_INIT is not set
CONFIG_HUDSON_XHCI_ENABLE=y
CONFIG_HUDSON_XHCI_FWM=y
CONFIG_HUDSON_IMC_FWM=y
# CONFIG_HUDSON_GEC_FWM is not set
CONFIG_HUDSON_XHCI_FWM_FILE="3rdparty/southbridge/amd/yangtze/xhci.bin"
CONFIG_HUDSON_IMC_FWM_FILE="3rdparty/southbridge/amd/yangtze/imc.bin"
CONFIG_HUDSON_FWM=y
CONFIG_HUDSON_FWM_POSITION=0xFFC20000
# CONFIG_HUDSON_SATA_IDE is not set
# CONFIG_HUDSON_SATA_RAID is not set
CONFIG_HUDSON_SATA_AHCI=y
# CONFIG_HUDSON_SATA_LEGACY_IDE is not set
# CONFIG_HUDSON_SATA_IDE2AHCI is not set
# CONFIG_HUDSON_SATA_AHCI7804 is not set
# CONFIG_HUDSON_SATA_IDE2AHCI7804 is not set
CONFIG_HUDSON_SATA_MODE=0x2
# CONFIG_HUDSON_AHCI_ROM is not set
CONFIG_AMD_SB_SPI_TX_LEN=64
CONFIG_SPI_FLASH=y
# CONFIG_SOUTHBRIDGE_INTEL_COMMON is not set
#
# Super I/O
#
#
# Embedded Controllers
#
#
# Devices
#
# CONFIG_MAINBOARD_HAS_NATIVE_VGA_INIT is not set
# CONFIG_VGA_ROM_RUN is not set
# CONFIG_ON_DEVICE_ROM_RUN is not set
# CONFIG_MULTIPLE_VGA_ADAPTERS is not set
CONFIG_PCI=y
# CONFIG_HYPERTRANSPORT_PLUGIN_SUPPORT is not set
CONFIG_PCIX_PLUGIN_SUPPORT=y
CONFIG_PCIEXP_PLUGIN_SUPPORT=y
CONFIG_AGP_PLUGIN_SUPPORT=y
CONFIG_CARDBUS_PLUGIN_SUPPORT=y
# CONFIG_AZALIA_PLUGIN_SUPPORT is not set
# CONFIG_PCIEXP_COMMON_CLOCK is not set
# CONFIG_PCIEXP_ASPM is not set
CONFIG_PCI_BUS_SEGN_BITS=0
#
# VGA BIOS
#
#
# PXE ROM
#
CONFIG_PXE_ROM=n
#
# Generic Drivers
#
# CONFIG_ELOG is not set
# CONFIG_IPMI_KCS is not set
# CONFIG_DRIVER_MAXIM_MAX77686 is not set
# CONFIG_DRIVERS_OXFORD_OXPCIE is not set
# CONFIG_DRIVER_PARADE_PS8625 is not set
# CONFIG_TPM is not set
# CONFIG_RTL8168_ROM_DISABLE is not set
# CONFIG_DRIVERS_SIL_3114 is not set
CONFIG_SPI_FLASH_EON=y
CONFIG_SPI_FLASH_MACRONIX=y
CONFIG_SPI_FLASH_SPANSION=y
CONFIG_SPI_FLASH_SST=y
CONFIG_SPI_FLASH_STMICRO=y
CONFIG_SPI_FLASH_WINBOND=y
# CONFIG_SPI_FLASH_NO_FAST_READ is not set
CONFIG_SPI_FLASH_GIGADEVICE=y
# CONFIG_DRIVER_TI_TPS65090 is not set
CONFIG_MMCONF_SUPPORT=y
#
# Console
#
CONFIG_EARLY_CONSOLE=y
CONFIG_SQUELCH_EARLY_SMP=y
CONFIG_CONSOLE_SERIAL=y
CONFIG_CONSOLE_SERIAL_COM1=y
# CONFIG_CONSOLE_SERIAL_COM2 is not set
# CONFIG_CONSOLE_SERIAL_COM3 is not set
# CONFIG_CONSOLE_SERIAL_COM4 is not set
CONFIG_CONSOLE_SERIAL_115200=y
# CONFIG_CONSOLE_SERIAL_57600 is not set
# CONFIG_CONSOLE_SERIAL_38400 is not set
# CONFIG_CONSOLE_SERIAL_19200 is not set
# CONFIG_CONSOLE_SERIAL_9600 is not set
# CONFIG_SPKMODEM is not set
CONFIG_HAVE_USBDEBUG=y
# CONFIG_HAVE_USBDEBUG_OPTIONS is not set
# CONFIG_USBDEBUG_IN_ROMSTAGE is not set
# CONFIG_CONSOLE_NE2K is not set
# CONFIG_CONSOLE_CBMEM is not set
# CONFIG_DEFAULT_CONSOLE_LOGLEVEL_8 is not set
# CONFIG_DEFAULT_CONSOLE_LOGLEVEL_7 is not set
# CONFIG_DEFAULT_CONSOLE_LOGLEVEL_6 is not set
CONFIG_DEFAULT_CONSOLE_LOGLEVEL_5=y
# CONFIG_DEFAULT_CONSOLE_LOGLEVEL_4 is not set
# CONFIG_DEFAULT_CONSOLE_LOGLEVEL_3 is not set
# CONFIG_DEFAULT_CONSOLE_LOGLEVEL_2 is not set
# CONFIG_DEFAULT_CONSOLE_LOGLEVEL_1 is not set
# CONFIG_DEFAULT_CONSOLE_LOGLEVEL_0 is not set
# CONFIG_CONSOLE_LOGBUF is not set
# CONFIG_NO_POST is not set
# CONFIG_CMOS_POST is not set
CONFIG_IO_POST=y
CONFIG_IO_POST_PORT=0x80
CONFIG_HAVE_UART_IO_MAPPED=y
# CONFIG_HAVE_UART_MEMORY_MAPPED is not set
# CONFIG_HAVE_UART_SPECIAL is not set
CONFIG_HAVE_ACPI_RESUME=y
# CONFIG_HAVE_ACPI_SLIC is not set
CONFIG_HAVE_HARD_RESET=y
CONFIG_HAVE_MONOTONIC_TIMER=y
# CONFIG_TIMER_QUEUE is not set
CONFIG_HAVE_OPTION_TABLE=y
# CONFIG_PIRQ_ROUTE is not set
# CONFIG_HAVE_SMI_HANDLER is not set
CONFIG_PCI_IO_CFG_EXT=y
CONFIG_CACHE_ROM_SIZE=0x400000
# CONFIG_USE_WATCHDOG_ON_BOOT is not set
# CONFIG_VGA is not set
CONFIG_GFXUMA=y
# CONFIG_RELOCATABLE_MODULES is not set
CONFIG_HAVE_ACPI_TABLES=y
CONFIG_HAVE_MP_TABLE=y
CONFIG_HAVE_PIRQ_TABLE=y
#
# System tables
#
CONFIG_MULTIBOOT=y
CONFIG_GENERATE_ACPI_TABLES=y
CONFIG_GENERATE_MP_TABLE=y
CONFIG_GENERATE_PIRQ_TABLE=y
CONFIG_GENERATE_SMBIOS_TABLES=y
#
# Payload
#
# CONFIG_PAYLOAD_NONE is not set
# CONFIG_PAYLOAD_ELF is not set
# CONFIG_PAYLOAD_LINUX is not set
CONFIG_PAYLOAD_SEABIOS=y
# CONFIG_PAYLOAD_FILO is not set
# CONFIG_PAYLOAD_GRUB2 is not set
# CONFIG_PAYLOAD_TIANOCORE is not set
CONFIG_SEABIOS_STABLE=y
# CONFIG_SEABIOS_MASTER is not set
CONFIG_PAYLOAD_FILE="$(obj)/seabios/out/bios.bin.elf"
CONFIG_COMPRESSED_PAYLOAD_LZMA=y
#
# Debugging
#
# CONFIG_GDB_STUB is not set
# CONFIG_DEBUG_CBFS is not set
# CONFIG_HAVE_DEBUG_RAM_SETUP is not set
# CONFIG_HAVE_DEBUG_CAR is not set
CONFIG_DEBUG_PIRQ=y
# CONFIG_HAVE_DEBUG_SMBUS is not set
# CONFIG_DEBUG_MALLOC is not set
# CONFIG_DEBUG_ACPI is not set
# CONFIG_DEBUG_SPI_FLASH is not set
# CONFIG_TRACE is not set
# CONFIG_RAMINIT_SYSINFO is not set
# CONFIG_ENABLE_APIC_EXT_ID is not set
CONFIG_WARNINGS_ARE_ERRORS=y
# CONFIG_POWER_BUTTON_DEFAULT_ENABLE is not set
# CONFIG_POWER_BUTTON_DEFAULT_DISABLE is not set
# CONFIG_POWER_BUTTON_FORCE_DISABLE is not set
# CONFIG_POWER_BUTTON_IS_OPTIONAL is not set
# CONFIG_CHROMEOS is not set