diff --git a/.gitmodules b/.gitmodules
index 2a5ebda..e4c2b5d 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -10,3 +10,6 @@
 [submodule "nanoprintf"]
 	path = nanoprintf
 	url = https://github.com/charlesnicholson/nanoprintf.git
+[submodule "seabios"]
+	path = seabios
+	url = https://github.com/FlyGoat/seabios-csmwrap.git
diff --git a/GNUmakefile b/GNUmakefile
index c3320aa..aa0057b 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -48,9 +48,10 @@ BUILD_VERSION := $(shell git describe --tags --always --dirty 2>/dev/null || ech
 # Check if CC is Clang.
 override CC_IS_CLANG := $(shell ! $(CC) --version 2>/dev/null | grep 'clang' >/dev/null 2>&1; echo $$?)
 
-# Save user CFLAGS and CPPFLAGS before we append internal flags.
+# Save user CFLAGS, CPPFLAGS, and LDFLAGS before we append internal flags.
 override USER_CFLAGS := $(CFLAGS)
 override USER_CPPFLAGS := $(CPPFLAGS)
+override USER_LDFLAGS := $(LDFLAGS)
 
 # Internal C flags that should not be changed by the user.
 override CFLAGS += \
@@ -259,3 +260,22 @@ clean:
 .PHONY: distclean
 distclean:
 	rm -rf bin-* obj-* ovmf
+
+# SeaBIOS build target.
+.PHONY: seabios
+seabios:
+	cp seabios-config seabios/.config
+	$(MAKE) -C seabios olddefconfig \
+		CC="$(CC)" \
+		OBJCOPY="$(OBJCOPY)" \
+		CFLAGS="$(USER_CFLAGS)" \
+		CPPFLAGS="$(USER_CPPFLAGS)" \
+		LDFLAGS="$(USER_LDFLAGS)"
+	$(MAKE) -C seabios \
+		CC="$(CC)" \
+		OBJCOPY="$(OBJCOPY)" \
+		CFLAGS="$(USER_CFLAGS)" \
+		CPPFLAGS="$(USER_CPPFLAGS)" \
+		LDFLAGS="$(USER_LDFLAGS)"
+	cd seabios/out && xxd -i Csm16.bin >../../src/bins/Csm16.h
+	cd seabios/out && xxd -i vgabios.bin >../../src/bins/vgabios.h
diff --git a/seabios b/seabios
new file mode 160000
index 0000000..e8cdc4f
--- /dev/null
+++ b/seabios
@@ -0,0 +1 @@
+Subproject commit e8cdc4ff818375157ec13dc2f0644f9ffe841c0f
diff --git a/seabios-config b/seabios-config
new file mode 100644
index 0000000..e55d81b
--- /dev/null
+++ b/seabios-config
@@ -0,0 +1,5 @@
+CONFIG_CSM=y
+# CONFIG_FLASH_FLOPPY is not set
+# CONFIG_VGAHOOKS is not set
+# CONFIG_TCGBIOS is not set
+CONFIG_VGA_COREBOOT=y
diff --git a/seabios/patches/0001-csm-Setup-PIC-in-PrepareToBoot.patch b/seabios/patches/0001-csm-Setup-PIC-in-PrepareToBoot.patch
deleted file mode 100644
index 2645302..0000000
--- a/seabios/patches/0001-csm-Setup-PIC-in-PrepareToBoot.patch
+++ /dev/null
@@ -1,27 +0,0 @@
-From c7849b92ea651c976ab0141e2b04e94ba73900d6 Mon Sep 17 00:00:00 2001
-From: Jiaxun Yang <jiaxun.yang@flygoat.com>
-Date: Fri, 9 May 2025 17:48:07 +0100
-Subject: [PATCH 1/2] csm: Setup PIC in PrepareToBoot
-
-This is required to get timer working.
-
-Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
----
- src/fw/csm.c | 1 +
- 1 file changed, 1 insertion(+)
-
-diff --git a/src/fw/csm.c b/src/fw/csm.c
-index 579debdcf4cc..ccd7645e1ce9 100644
---- a/src/fw/csm.c
-+++ b/src/fw/csm.c
-@@ -184,6 +184,7 @@ handle_csm_0002(struct bregs *regs)
-     struct bios_data_area_s *bda = MAKE_FLATPTR(SEG_BDA, 0);
-     bda->hdcount = 0;
- 
-+    pic_setup();
-     thread_setup();
-     mathcp_setup();
-     timer_setup();
--- 
-2.39.5 (Apple Git-154)
-