initial commit

Makefile

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+CONFIG=free-defconfig-d5c31acee4
+SDK_VERSION=2022-04-04_9a8d0a03db
+BOOTSPLASH=bootsplash.jpg
+# BOOTORDER=bootorder
+REPO_URL=https://github.com/coreboot/coreboot.git
+COMMIT=d5c31acee4
+
+COREBOOT_CONFIG=coreboot/.config
+BUILDER=./coreboot-sdk.sh \
+		--config $(CONFIG) \
+		--sdk-version $(SDK_VERSION) \
+		--bootsplash $(BOOTSPLASH)
+#--bootorder $(BOOTORDER)
+
+.PHONY: clean nuke defconfig checkout flash
+
+build/coreboot_top_prepared_12mb.rom: build/coreboot_top.rom
+	dd if=/dev/zero of="$@" bs=4M count=2 status=none
+	dd if="$<" oflag=append conv=notrunc of="$@" bs=4M status=none
+
+build/coreboot_top.rom.sha256: build/coreboot_top.rom
+	sha256sum "$<" > "$@"
+
+build/coreboot_top.rom: build/coreboot.rom
+	dd if="$<" of="$@" bs=1M skip=8
+
+build/coreboot.rom: $(COREBOOT_CONFIG) $(BOOTSPLASH) $(bootorder)
+	mkdir -p build
+	$(BUILDER) make
+
+$(COREBOOT_CONFIG): $(CONFIG) checkout
+	mkdir -p build
+	$(BUILDER) make defconfig
+
+defconfig: $(COREBOOT_CONFIG)
+
+coreboot:  # clone
+	git clone $(REPO_URL) $@
+	git -C coreboot submodule update --init --recursive --remote
+
+checkout: coreboot
+	git -C coreboot checkout $(COMMIT)
+	git -C coreboot submodule update --recursive --remote
+
+clean:
+	rm -rf coreboot/.config
+	rm -rf build
+
+nuke: clean
+	rm -rf coreboot
+
+flash: build/coreboot_top_prepared_12mb.rom layout.txt
+	flashrom \
+		--force \
+		--noverify-all\
+		-p internal \
+		--layout layout.txt \
+		--image bios \
+		-w build/coreboot_top_prepared_12mb.rom

README.md

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+# coreboot-builder
+
+This is what I use to build my coreboot images. It is heavily based on the
+scripts and configurations used by [skulls](https://github.com/merge/skulls).
+But simplified to support only my very specific hardware and preferences. This
+makes it leaner to use and easier for me to understand it, so it's easier to
+customize (for example, if I want to change the boot order).
+
+Currently I have only one config for my Thinkpad X230; `capibara`, and I use a
+the "free" config (with the VGA BIOS SeaVGABIOS instead of the Intel one).
+
+## Build process
+
+I use a Makefile to orchestrate cloning the coreboot code, checking out the
+right commit, compiling the image, flashing it, etc.
+The coreboot SDK is run from a docker image because I couldn't manage to
+compile everything otherwise.
+
+## Splash screen
+
+For an X230 the splash screen image needs to be a JPEG using:
+
+* with "progressive" turned off
+* "4:2:0 (chroma quartered)" Subsampling
+* 1024px wide and 768px tall
+
+But the X230 screen happens to be 16:9 (1366px wide, 768px tall). When the
+SaBIOSVABIOS is used, the image is just shown centered in the screen, with
+black blocks on each side. When the Intel VGA is used, the image is stretched
+to fill the whole 1366 x 768 screen. So make sure to plan accordingly to make
+the image look right.
+
+Also, the SeaBIOS VGA seems to show weird colors when booting. I don't know
+how to fix that, so I just keep the image pure black and white to make it look
+decent.
+
+## Updates
+
+I try to follow skull's releases and update the coreboot commit, sdk version
+and config as they do it.
+
+Last release happened on 2022/05/03.
+
+## Flashing
+
+Before flashing, the system needs to boot with the kernel parameter
+`iomem=relaxed`.
+
+* Reboot the computer
+* When the GRUB screen appears, press `e` to edit the startup command
+* Append `iomem=relaxed` to the kernel command
+* Press `ctrl-x` or `F2` to boot the system with the modification
+* Then flash the new image with:
+
+```sh
+flash: build/coreboot_top_prepared_12mb.rom layout.txt
+	flashrom \
+		--force \
+		--noverify-all\
+		-p internal \
+		--layout layout.txt \
+		--image bios \
+		-w build/coreboot_top_prepared_12mb.rom
+```

coreboot-sdk.sh

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+#!/bin/sh
+
+while :; do
+    case "$1" in
+        --config)
+            CONFIG="$2"
+            shift 2;;
+        --sdk-version)
+            SDK_VERSION="$2"
+            shift 2;;
+        --bootorder)
+            BOOTORDER="$2"
+            shift 2;;
+        --bootsplash)
+            BOOTSPLASH="$2"
+            shift 2;;
+        *)
+            break;;
+    esac
+done
+
+uid=$(id -u)
+gid=$(id -g)
+
+docker run --rm -it \
+    --user "$uid:$gid" \
+    --workdir "/home/coreboot/cb_build" \
+    -v "$(pwd)/coreboot:/home/coreboot/cb_build" \
+    -v "$(pwd)/build:/home/coreboot/cb_build/build" \
+    -v "$(pwd)/${CONFIG}:/home/coreboot/cb_build/configs/defconfig:ro" \
+    -v "$(pwd)/${BOOTSPLASH}:/home/coreboot/cb_build/bootsplash.jpg:ro" \
+    coreboot/coreboot-sdk:"$SDK_VERSION" \
+    "$@"
+
+#    -v "$(pwd)/${BOOTORDER}:/home/coreboot/cb_build/bootorder:ro" \

free-defconfig-d5c31acee4

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+CONFIG_BOOTSPLASH_IMAGE=y
+CONFIG_VENDOR_LENOVO=y
+CONFIG_NO_POST=y
+CONFIG_CBFS_SIZE=0x400000
+CONFIG_LINEAR_FRAMEBUFFER_MAX_HEIGHT=768
+CONFIG_LINEAR_FRAMEBUFFER_MAX_WIDTH=1024
+CONFIG_ONBOARD_VGA_IS_PRIMARY=y
+CONFIG_SEABIOS_PS2_TIMEOUT=5000
+CONFIG_CONSOLE_CBMEM_BUFFER_SIZE=0x20000
+CONFIG_PCIEXP_HOTPLUG_BUSES=8
+CONFIG_PCIEXP_HOTPLUG_MEM=0x800000
+CONFIG_PCIEXP_HOTPLUG_PREFETCH_MEM=0x10000000
+CONFIG_BOARD_LENOVO_X230=y
+CONFIG_UART_PCI_ADDR=0x0
+# CONFIG_H8_BEEP_ON_DEATH is not set
+CONFIG_H8_SUPPORT_BT_ON_WIFI=y
+CONFIG_BOOTBLOCK_NORMAL=y
+CONFIG_GENERIC_LINEAR_FRAMEBUFFER=y
+CONFIG_BOOTSPLASH=y
+CONFIG_PCIEXP_HOTPLUG_IO=0x2000
+CONFIG_SUBSYSTEM_VENDOR_ID=0x0000
+CONFIG_SUBSYSTEM_DEVICE_ID=0x0000
+CONFIG_I2C_TRANSFER_TIMEOUT_US=500000
+CONFIG_DEFAULT_CONSOLE_LOGLEVEL_8=y
+CONFIG_SEABIOS_DEBUG_LEVEL=-1
+CONFIG_COREINFO_SECONDARY_PAYLOAD=y
+CONFIG_NVRAMCUI_SECONDARY_PAYLOAD=y
+# CONFIG_SEABIOS_BOOTORDER_FILE="bootorder"

layout.txt

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+0x00000000:0x00000fff ifd
+0x00001000:0x00002fff gbe
+0x00003000:0x004fffff me
+0x00500000:0x007fffff unused
+0x00800000:0x00bfffff bios