diff --git a/src/system/runtime_loader/Jamfile b/src/system/runtime_loader/Jamfile
index 5476f5da01..46239d120e 100644
--- a/src/system/runtime_loader/Jamfile
+++ b/src/system/runtime_loader/Jamfile
@@ -1,6 +1,11 @@
 SubDir HAIKU_TOP src system runtime_loader ;
 
 
+if $(TARGET_ARCH) = x86_64
+	&& ( x86 in $(HAIKU_ARCHS[2-]) || x86_gcc2 in $(HAIKU_ARCHS[2-]) ) {
+	DEFINES += _COMPAT_MODE ;
+}
+
 local architectureObject ;
 for architectureObject in [ MultiArchSubDirSetup ] {
 	on $(architectureObject) {
diff --git a/src/system/runtime_loader/arch/x86/Jamfile b/src/system/runtime_loader/arch/x86/Jamfile
index 444c3211b0..68cb226dd0 100644
--- a/src/system/runtime_loader/arch/x86/Jamfile
+++ b/src/system/runtime_loader/arch/x86/Jamfile
@@ -16,7 +16,12 @@ for architectureObject in [ MultiArchSubDirSetup x86 x86_gcc2 ] {
 			<src!system!libroot!os!arch!$(TARGET_ARCH)!$(architecture)>atomic.o
 			<src!system!libroot!os!arch!$(TARGET_ARCH)!$(architecture)>thread.o
 
-			<src!system!libroot!posix!string!arch!$(TARGET_ARCH)!$(architecture)>arch_string.o
+			[ MultiArchIfPrimary
+				<src!system!libroot!posix!string!arch!$(TARGET_ARCH)!$(architecture)>memcpy.o
+				<src!system!libroot!posix!string!arch!$(TARGET_ARCH)!$(architecture)>memset.o
+				:
+				<src!system!libroot!posix!string!arch!$(TARGET_ARCH)!$(architecture)>arch_string.o
+				: x86_64 ]
 			;
 	}
 }
diff --git a/src/system/runtime_loader/elf.cpp b/src/system/runtime_loader/elf.cpp
index 03b8bd1c73..018315955d 100644
--- a/src/system/runtime_loader/elf.cpp
+++ b/src/system/runtime_loader/elf.cpp
@@ -1012,6 +1012,33 @@ elf_verify_header(void *header, size_t length)
 }
 
 
+#ifdef _COMPAT_MODE
+#ifdef __x86_64__
+status_t
+elf32_verify_header(void *header, size_t length)
+{
+	int32 programSize, sectionSize;
+
+	if (length < sizeof(Elf32_Ehdr))
+		return B_NOT_AN_EXECUTABLE;
+
+	return parse_elf32_header((Elf32_Ehdr *)header, &programSize, &sectionSize);
+}
+#else
+status_t
+elf64_verify_header(void *header, size_t length)
+{
+	int32 programSize, sectionSize;
+
+	if (length < sizeof(Elf64_Ehdr))
+		return B_NOT_AN_EXECUTABLE;
+
+	return parse_elf64_header((Elf64_Ehdr *)header, &programSize, &sectionSize);
+}
+#endif	// __x86_64__
+#endif	// _COMPAT_MODE
+
+
 void
 terminate_program(void)
 {
diff --git a/src/system/runtime_loader/elf_load_image.cpp b/src/system/runtime_loader/elf_load_image.cpp
index 3822f36266..ebd3f41b0f 100644
--- a/src/system/runtime_loader/elf_load_image.cpp
+++ b/src/system/runtime_loader/elf_load_image.cpp
@@ -421,6 +421,61 @@ parse_elf_header(elf_ehdr* eheader, int32* _pheaderSize,
 }
 
 
+#if defined(_COMPAT_MODE)
+#if defined(__x86_64__)
+status_t
+parse_elf32_header(Elf32_Ehdr* eheader, int32* _pheaderSize,
+	int32* _sheaderSize)
+{
+	if (memcmp(eheader->e_ident, ELFMAG, 4) != 0)
+		return B_NOT_AN_EXECUTABLE;
+
+	if (eheader->e_ident[4] != ELFCLASS32)
+		return B_NOT_AN_EXECUTABLE;
+
+	if (eheader->e_phoff == 0)
+		return B_NOT_AN_EXECUTABLE;
+
+	if (eheader->e_phentsize < sizeof(Elf32_Phdr))
+		return B_NOT_AN_EXECUTABLE;
+
+	*_pheaderSize = eheader->e_phentsize * eheader->e_phnum;
+	*_sheaderSize = eheader->e_shentsize * eheader->e_shnum;
+
+	if (*_pheaderSize <= 0 || *_sheaderSize <= 0)
+		return B_NOT_AN_EXECUTABLE;
+
+	return B_OK;
+}
+#else
+status_t
+parse_elf64_header(Elf64_Ehdr* eheader, int32* _pheaderSize,
+	int32* _sheaderSize)
+{
+	if (memcmp(eheader->e_ident, ELFMAG, 4) != 0)
+		return B_NOT_AN_EXECUTABLE;
+
+	if (eheader->e_ident[4] != ELFCLASS64)
+		return B_NOT_AN_EXECUTABLE;
+
+	if (eheader->e_phoff == 0)
+		return B_NOT_AN_EXECUTABLE;
+
+	if (eheader->e_phentsize < sizeof(Elf64_Phdr))
+		return B_NOT_AN_EXECUTABLE;
+
+	*_pheaderSize = eheader->e_phentsize * eheader->e_phnum;
+	*_sheaderSize = eheader->e_shentsize * eheader->e_shnum;
+
+	if (*_pheaderSize <= 0 || *_sheaderSize <= 0)
+		return B_NOT_AN_EXECUTABLE;
+
+	return B_OK;
+}
+#endif	// __x86_64__
+#endif	// _COMPAT_MODE
+
+
 status_t
 load_image(char const* name, image_type type, const char* rpath,
 	const char* requestingObjectPath, image_t** _image)
@@ -574,6 +629,9 @@ load_image(char const* name, image_type type, const char* rpath,
 	// loading) we init the search path subdir if the compiler version doesn't
 	// match ours.
 	if (sSearchPathSubDir == NULL) {
+#if defined(_COMPAT_MODE) && !defined(__x86_64__)
+		sSearchPathSubDir = "x86";
+#else
 		#if __GNUC__ == 2
 			if ((image->abi & B_HAIKU_ABI_MAJOR) == B_HAIKU_ABI_GCC_4)
 				sSearchPathSubDir = "x86";
@@ -581,6 +639,7 @@ load_image(char const* name, image_type type, const char* rpath,
 			if ((image->abi & B_HAIKU_ABI_MAJOR) == B_HAIKU_ABI_GCC_2)
 				sSearchPathSubDir = "x86_gcc2";
 		#endif
+#endif
 	}
 
 	set_abi_version(image->abi);
diff --git a/src/system/runtime_loader/elf_load_image.h b/src/system/runtime_loader/elf_load_image.h
index 77ead88b86..061c0677ae 100644
--- a/src/system/runtime_loader/elf_load_image.h
+++ b/src/system/runtime_loader/elf_load_image.h
@@ -10,6 +10,15 @@
 
 status_t	parse_elf_header(elf_ehdr* eheader, int32* _pheaderSize,
 				int32* _sheaderSize);
+#if defined(_COMPAT_MODE)
+	#if defined(__x86_64__)
+status_t	parse_elf32_header(Elf32_Ehdr* eheader, int32* _pheaderSize,
+	int32* _sheaderSize);
+	#else
+status_t	parse_elf64_header(Elf64_Ehdr* eheader, int32* _pheaderSize,
+	int32* _sheaderSize);
+	#endif
+#endif
 status_t	load_image(char const* name, image_type type, const char* rpath,
 				const char* requestingObjectPath, image_t** _image);
 
diff --git a/src/system/runtime_loader/runtime_loader.cpp b/src/system/runtime_loader/runtime_loader.cpp
index 3aa9cc34e8..e632895e92 100644
--- a/src/system/runtime_loader/runtime_loader.cpp
+++ b/src/system/runtime_loader/runtime_loader.cpp
@@ -416,6 +416,15 @@ test_executable(const char *name, char *invoker)
 	}
 
 	status = elf_verify_header(buffer, length);
+#ifdef _COMPAT_MODE
+#ifdef __x86_64__
+	if (status == B_NOT_AN_EXECUTABLE)
+		status = elf32_verify_header(buffer, length);
+#else
+	if (status == B_NOT_AN_EXECUTABLE)
+		status = elf64_verify_header(buffer, length);
+#endif	// __x86_64__
+#endif	// _COMPAT_MODE
 	if (status == B_NOT_AN_EXECUTABLE) {
 		if (!strncmp(buffer, "#!", 2)) {
 			// test for shell scripts
diff --git a/src/system/runtime_loader/runtime_loader_private.h b/src/system/runtime_loader/runtime_loader_private.h
index be40233378..5df7dc6b7a 100644
--- a/src/system/runtime_loader/runtime_loader_private.h
+++ b/src/system/runtime_loader/runtime_loader_private.h
@@ -30,12 +30,17 @@
 #	define KTRACE(x...)
 #endif	// RUNTIME_LOADER_TRACING
 
-
+#if defined(_COMPAT_MODE) && !defined(__x86_64__)
+#define RLD_PREFIX "runtime_loader_compat: "
+#endif
+#ifndef RLD_PREFIX
+#define RLD_PREFIX "runtime_loader: "
+#endif
 #define FATAL(x...)							\
 	do {									\
-		dprintf("runtime_loader: " x);		\
+		dprintf(RLD_PREFIX x);		\
 		if (!gProgramLoaded)				\
-			printf("runtime_loader: " x);	\
+			printf(RLD_PREFIX x);	\
 	} while (false)
 
 
@@ -81,6 +86,13 @@ int resolve_symbol(image_t* rootImage, image_t* image, elf_sym* sym,
 
 
 status_t elf_verify_header(void* header, size_t length);
+#ifdef _COMPAT_MODE
+#ifdef __x86_64__
+status_t elf32_verify_header(void *header, size_t length);
+#else
+status_t elf64_verify_header(void *header, size_t length);
+#endif	// __x86_64__
+#endif	// _COMPAT_MODE
 void rldelf_init(void);
 void rldexport_init(void);
 void set_abi_version(int abi_version);