diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..be77eab
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "gnu-efi"]
+	path = gnu-efi
+	url = https://github.com/rhboot/gnu-efi.git
diff --git a/Makefile b/Makefile
index c7cf855..e5d6dd5 100644
--- a/Makefile
+++ b/Makefile
@@ -1,13 +1,11 @@
 CC      = $(CC_PREFIX)-gcc
 CFLAGS  = -std=c11 -O2 -ffreestanding -mno-red-zone -fno-stack-protector -Wshadow -Wall -Wunused -Werror-implicit-function-declaration -Werror
 CFLAGS += -I$(GNUEFI_INC) -I$(GNUEFI_INC)/$(GNUEFI_ARCH) -I$(GNUEFI_INC)/protocol
-LDFLAGS = -nostdlib -shared -Wl,-dll -Wl,--subsystem,10 -e _EfiMain
-LIBS    = -L$(GNUEFI_LIB) -lefi -lgcc
+LDFLAGS = -nostdlib -shared -Wl,-dll -Wl,--subsystem,10 -e efi_main -s
 
 GNUEFI_INC = /usr/$(CC_PREFIX)/include/efi
-GNUEFI_LIB = /usr/$(CC_PREFIX)/lib
 
-FILES_C = src/main.c src/util.c src/types.c src/config.c src/sbat.c
+FILES_C = src/main.c src/util.c src/types.c src/config.c src/sbat.c src/efi.c
 FILES_H = $(wildcard src/*.h)
 FILES_CS = src/Setup.cs src/Esp.cs src/Efi.cs
 GIT_DESCRIBE := $(firstword $(GIT_DESCRIBE) $(shell git describe --tags) unknown)
@@ -59,13 +57,13 @@ efi/bootx64.efi: CC_PREFIX = x86_64-w64-mingw32
 efi/bootx64.efi: GNUEFI_ARCH = x86_64
 efi/bootx64.efi: $(FILES_C)
 	@mkdir -p efi
-	$(CC) $(CFLAGS) $(LDFLAGS) $^ -o $@ $(LIBS) -s
+	$(CC) $(CFLAGS) $(LDFLAGS) $^ -o $@
 
 efi/bootia32.efi: CC_PREFIX = i686-w64-mingw32
 efi/bootia32.efi: GNUEFI_ARCH = ia32
 efi/bootia32.efi: $(FILES_C)
 	@mkdir -p efi
-	$(CC) $(CFLAGS) $(LDFLAGS) $^ -o $@ $(LIBS) -s
+	$(CC) $(CFLAGS) $(LDFLAGS) $^ -o $@
 
 clean:
 	rm -rf setup.exe efi efi-signed
diff --git a/gnu-efi b/gnu-efi
new file mode 160000
index 0000000..965f557
--- /dev/null
+++ b/gnu-efi
@@ -0,0 +1 @@
+Subproject commit 965f557ab7d9cb87993ea43bbbc6514c3d28f6bb
diff --git a/src/config.c b/src/config.c
index c038f0b..fd9b663 100644
--- a/src/config.c
+++ b/src/config.c
@@ -1,8 +1,6 @@
 #include "config.h"
 #include "util.h"
 
-#include <efilib.h>
-
 BOOLEAN ReadConfigFile(struct HackBGRT_config* config, EFI_FILE_HANDLE root_dir, const CHAR16* path) {
 	void* data = 0;
 	UINTN data_bytes = 0;
diff --git a/src/config.h b/src/config.h
index c9e0c1d..b6261fc 100644
--- a/src/config.h
+++ b/src/config.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#include <efi.h>
+#include "efi.h"
 
 /**
  * Possible actions to perform on the BGRT.
diff --git a/src/efi.c b/src/efi.c
new file mode 100644
index 0000000..fbf713f
--- /dev/null
+++ b/src/efi.c
@@ -0,0 +1,159 @@
+#include "efi.h"
+#include "util.h"
+
+// New implementations of some functions in gnu-efi.
+// These functions are designed to avoid other gnu-efi calls.
+
+EFI_STATUS LibLocateProtocol(IN EFI_GUID *ProtocolGuid, OUT VOID **Interface) {
+	EFI_HANDLE buffer[256];
+	UINTN size = sizeof(buffer);
+	if (!EFI_ERROR(BS->LocateHandle(ByProtocol, ProtocolGuid, NULL, &size, buffer))) {
+		for (int i = 0; i < size / sizeof(EFI_HANDLE); ++i) {
+			if (!EFI_ERROR(BS->HandleProtocol(buffer[i], ProtocolGuid, Interface))) {
+				return EFI_SUCCESS;
+			}
+		}
+	}
+	return EFI_NOT_FOUND;
+}
+
+EFI_DEVICE_PATH *FileDevicePath(IN EFI_HANDLE Device OPTIONAL, IN CHAR16 *FileName) {
+	EFI_DEVICE_PATH *old_path = 0;
+	if (!Device || EFI_ERROR(BS->HandleProtocol(Device, TmpGuidPtr((EFI_GUID) EFI_DEVICE_PATH_PROTOCOL_GUID), (void**)&old_path))) {
+		static EFI_DEVICE_PATH end_path = {END_DEVICE_PATH_TYPE, END_ENTIRE_DEVICE_PATH_SUBTYPE, {sizeof(end_path), 0}};
+		old_path = &end_path;
+	}
+	UINTN old_path_size = 0, instances = 0;
+	for (EFI_DEVICE_PATH *p0 = old_path;; p0 = NextDevicePathNode(p0)) {
+		old_path_size += DevicePathNodeLength(p0);
+		if (IsDevicePathEndType(p0)) {
+			instances += 1;
+		}
+		if (IsDevicePathEnd(p0)) {
+			break;
+		}
+	}
+
+	UINTN size_str = (StrLen(FileName) + 1) * sizeof(*FileName);
+	UINTN size_fdp = SIZE_OF_FILEPATH_DEVICE_PATH + size_str;
+
+	EFI_DEVICE_PATH *new_path;
+	if (EFI_ERROR(BS->AllocatePool(EfiBootServicesData, old_path_size + instances * size_fdp, (void**)&new_path))) {
+		return 0;
+	}
+
+	EFI_DEVICE_PATH *p1 = new_path;
+	for (EFI_DEVICE_PATH *p0 = old_path;; p0 = NextDevicePathNode(p0)) {
+		if (IsDevicePathEndType(p0)) {
+			*p1 = (EFI_DEVICE_PATH) {
+				.Type = MEDIA_DEVICE_PATH,
+				.SubType = MEDIA_FILEPATH_DP,
+				.Length = {size_fdp, size_fdp >> 8},
+			};
+			FILEPATH_DEVICE_PATH *f = (FILEPATH_DEVICE_PATH *) p1;
+			BS->CopyMem(f->PathName, FileName, size_str);
+			p1 = NextDevicePathNode(p1);
+		}
+		BS->CopyMem(p1, p0, DevicePathNodeLength(p0));
+		if (IsDevicePathEnd(p0)) {
+			break;
+		}
+		p1 = NextDevicePathNode(p1);
+	}
+
+	return new_path;
+}
+
+INTN CompareMem(IN CONST VOID *Dest, IN CONST VOID *Src, IN UINTN len) {
+	CONST UINT8 *d = Dest, *s = Src;
+	for (UINTN i = 0; i < len; ++i) {
+		if (d[i] != s[i]) {
+			return d[i] - s[i];
+		}
+	}
+	return 0;
+}
+
+void StrnCat(IN CHAR16* dest, IN CONST CHAR16* src, UINTN len) {
+	CHAR16* d = dest;
+	while (*d) {
+		++d;
+	}
+	while (len-- && *src) {
+		*d++ = *src++;
+	}
+	*d = 0;
+}
+
+UINTN StrLen(IN CONST CHAR16* s) {
+	UINTN i = 0;
+	while (*s++) {
+		++i;
+	}
+	return i;
+}
+
+INTN StriCmp(IN CONST CHAR16* s1, IN CONST CHAR16* s2) {
+	while (*s1 && *s2) {
+		CHAR16 c1 = *s1++, c2 = *s2++;
+		if (c1 >= 'A' && c1 <= 'Z') {
+			c1 += 'a' - 'A';
+		}
+		if (c2 >= 'A' && c2 <= 'Z') {
+			c2 += 'a' - 'A';
+		}
+		if (c1 != c2) {
+			return c1 - c2;
+		}
+	}
+	return *s1 - *s2;
+}
+
+INTN StrnCmp(IN CONST CHAR16* s1, IN CONST CHAR16* s2, UINTN len) {
+	while (*s1 && *s2 && len--) {
+		CHAR16 c1 = *s1++, c2 = *s2++;
+		if (c1 >= 'A' && c1 <= 'Z') {
+			c1 += 'a' - 'A';
+		}
+		if (c2 >= 'A' && c2 <= 'Z') {
+			c2 += 'a' - 'A';
+		}
+		if (c1 != c2) {
+			return c1 - c2;
+		}
+	}
+	return len ? *s1 - *s2 : 0;
+}
+
+INTN StrCmp(IN CONST CHAR16* s1, IN CONST CHAR16* s2) {
+	while (*s1 && *s2) {
+		if (*s1 != *s2) {
+			return *s1 - *s2;
+		}
+		++s1, ++s2;
+	}
+	return *s1 - *s2;
+}
+
+UINTN Atoi(IN CONST CHAR16* s) {
+	UINTN n = 0;
+	while (*s >= '0' && *s <= '9') {
+		n = n * 10 + *s++ - '0';
+	}
+	return n;
+}
+
+void *memset(void *s, int c, __SIZE_TYPE__ n) {
+	unsigned char *p = s;
+	while (n--)
+		*p++ = c;
+	return s;
+}
+
+void *memcpy(void *dest, const void *src, __SIZE_TYPE__ n) {
+	const unsigned char *q = src;
+	unsigned char *p = dest;
+	while (n--)
+		*p++ = *q++;
+	return dest;
+}
diff --git a/src/efi.h b/src/efi.h
new file mode 100644
index 0000000..d440649
--- /dev/null
+++ b/src/efi.h
@@ -0,0 +1,5 @@
+#pragma once
+
+#include <stdint.h>
+#include <efi.h>
+#include <efilib.h>
diff --git a/src/main.c b/src/main.c
index 251633c..e28199a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,6 +1,4 @@
-#include <efi.h>
-#include <efilib.h>
-
+#include "efi.h"
 #include "types.h"
 #include "config.h"
 #include "util.h"
@@ -14,6 +12,10 @@
 	const CHAR16 version[] = L"unknown; not an official release?";
 #endif
 
+EFI_SYSTEM_TABLE *ST;
+EFI_BOOT_SERVICES *BS;
+EFI_RUNTIME_SERVICES *RT;
+
 /**
  * The configuration.
  */
@@ -404,8 +406,11 @@ static EFI_HANDLE LoadApp(int print_failure, EFI_HANDLE image_handle, EFI_LOADED
 /**
  * The main program.
  */
-EFI_STATUS EFIAPI EfiMain(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE *ST_) {
-	InitializeLib(image_handle, ST_);
+EFI_STATUS EFIAPI efi_main(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE *ST_) {
+	ST = ST_;
+	BS = ST_->BootServices;
+	RT = ST_->RuntimeServices;
+
 	Log(0, L"HackBGRT version: %s\n", version);
 
 	EFI_LOADED_IMAGE* image;
@@ -504,12 +509,3 @@ EFI_STATUS EFIAPI EfiMain(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE *ST_) {
 		return 1;
 	}
 }
-
-/**
- * Forward to EfiMain.
- *
- * Some compilers and architectures differ in underscore handling. This helps.
- */
-EFI_STATUS EFIAPI _EfiMain(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE *ST_) {
-	return EfiMain(image_handle, ST_);
-}
diff --git a/src/types.h b/src/types.h
index 3bb42a3..34e0c8e 100644
--- a/src/types.h
+++ b/src/types.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#include <efi.h>
+#include "efi.h"
 
 #pragma pack(push, 1)
 
diff --git a/src/util.c b/src/util.c
index 1bd8129..d7a34c0 100644
--- a/src/util.c
+++ b/src/util.c
@@ -1,7 +1,5 @@
 #include "util.h"
 
-#include <efilib.h>
-
 const CHAR16* TmpStr(CHAR8 *src, int length) {
 	static CHAR16 arr[4][16];
 	static int j;
diff --git a/src/util.h b/src/util.h
index 3785fd4..a83cd6d 100644
--- a/src/util.h
+++ b/src/util.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#include <efi.h>
+#include "efi.h"
 
 /**
  * Convert a short ASCII string to UCS2, store in a static array.