diff --git a/Makefile b/Makefile
index 5bd7158..bd2cc10 100644
--- a/Makefile
+++ b/Makefile
@@ -376,6 +376,7 @@
 # (of course), but should come after any lines setting CC because the line
 # below uses CC itself.
 override ARCH := $(strip $(call debug_shell,$(CC) $(CPPFLAGS) -E archtest.c 2>/dev/null | grep -v '^\#' | grep '"' | cut -f 2 -d'"'))
+override ENDIAN := $(strip $(call debug_shell,$(CC) $(CPPFLAGS) -E endiantest.c 2>/dev/null | grep -v '^\#'))
 
 # PCI port I/O support is unimplemented on PPC/MIPS/SPARC and unavailable on ARM.
 # Right now this means the drivers below only work on x86.
diff --git a/endiantest.c b/endiantest.c
new file mode 100644
index 0000000..de44ec5
--- /dev/null
+++ b/endiantest.c
@@ -0,0 +1,6 @@
+#include "platform.h"
+#if __FLASHROM_LITTLE_ENDIAN__
+little
+#else
+big
+#endif
diff --git a/hwaccess.h b/hwaccess.h
index b006d05..bc5cb9b 100644
--- a/hwaccess.h
+++ b/hwaccess.h
@@ -43,89 +43,6 @@
 #undef index
 #endif /* NEED_PCI == 1 */
 
-
-/* The next big hunk tries to guess endianess from various preprocessor macros */
-/* First some error checking in case some weird header has defined both.
- * NB: OpenBSD always defines _BIG_ENDIAN and _LITTLE_ENDIAN. */
-#if defined (__LITTLE_ENDIAN__) && defined (__BIG_ENDIAN__)
-#error Conflicting endianness #define
-#endif
-
-#if IS_X86
-
-/* All x86 is little-endian. */
-#define __FLASHROM_LITTLE_ENDIAN__ 1
-
-#elif IS_MIPS
-
-/* MIPS can be either endian. */
-#if defined (__MIPSEL) || defined (__MIPSEL__) || defined (_MIPSEL) || defined (MIPSEL)
-#define __FLASHROM_LITTLE_ENDIAN__ 1
-#elif defined (__MIPSEB) || defined (__MIPSEB__) || defined (_MIPSEB) || defined (MIPSEB)
-#define __FLASHROM_BIG_ENDIAN__ 1
-#endif
-
-#elif IS_PPC
-
-/* PowerPC can be either endian. */
-#if defined (_BIG_ENDIAN) || defined (__BIG_ENDIAN__)
-#define __FLASHROM_BIG_ENDIAN__ 1
-#elif defined (_LITTLE_ENDIAN) || defined (__LITTLE_ENDIAN__)
-#define __FLASHROM_LITTLE_ENDIAN__ 1
-#endif
-
-#elif IS_ARM
-
-/* ARM can be either endian. */
-#if defined (__ARMEB__)
-#define __FLASHROM_BIG_ENDIAN__ 1
-#elif defined (__ARMEL__)
-#define __FLASHROM_LITTLE_ENDIAN__ 1
-#endif
-
-#elif IS_SPARC
-/* SPARC is big endian in general (but allows to access data in little endian too). */
-#define __FLASHROM_BIG_ENDIAN__ 1
-
-#endif /* IS_? */
-
-#if !defined (__FLASHROM_BIG_ENDIAN__) && !defined (__FLASHROM_LITTLE_ENDIAN__)
-
-/* If architecture-specific approaches fail try generic variants. First: BSD (works about everywhere). */
-#if !IS_WINDOWS
-#include <sys/param.h>
-
-#if defined (__BYTE_ORDER)
-#if __BYTE_ORDER == __LITTLE_ENDIAN
-#define __FLASHROM_LITTLE_ENDIAN__
-#elif __BYTE_ORDER == __BIG_ENDIAN
-#define __FLASHROM_BIG_ENDIAN__
-#else
-#error Unknown byte order!
-#endif
-#endif /* defined __BYTE_ORDER */
-#endif /* !IS_WINDOWS */
-
-#if !defined (__FLASHROM_BIG_ENDIAN__) && !defined (__FLASHROM_LITTLE_ENDIAN__)
-
-/* Nonstandard libc-specific macros for determining endianness. */
-/* musl provides an endian.h as well... but it can not be detected from within C. */
-#if defined(__GLIBC__)
-#include <endian.h>
-#if BYTE_ORDER == LITTLE_ENDIAN
-#define __FLASHROM_LITTLE_ENDIAN__ 1
-#elif BYTE_ORDER == BIG_ENDIAN
-#define __FLASHROM_BIG_ENDIAN__ 1
-#endif
-#endif
-#endif
-
-#endif
-
-#if !defined (__FLASHROM_BIG_ENDIAN__) && !defined (__FLASHROM_LITTLE_ENDIAN__)
-#error Unable to determine endianness.
-#endif
-
 #define ___constant_swab8(x) ((uint8_t) (				\
 	(((uint8_t)(x) & (uint8_t)0xffU))))
 
diff --git a/platform.h b/platform.h
index b2fdcd0..e3b7674 100644
--- a/platform.h
+++ b/platform.h
@@ -81,4 +81,86 @@
 #error Unknown architecture
 #endif
 
+/* The next big hunk tries to guess endianess from various preprocessor macros */
+/* First some error checking in case some weird header has defined both.
+ * NB: OpenBSD always defines _BIG_ENDIAN and _LITTLE_ENDIAN. */
+#if defined (__LITTLE_ENDIAN__) && defined (__BIG_ENDIAN__)
+#error Conflicting endianness #define
+#endif
+
+#if IS_X86
+
+/* All x86 is little-endian. */
+#define __FLASHROM_LITTLE_ENDIAN__ 1
+
+#elif IS_MIPS
+
+/* MIPS can be either endian. */
+#if defined (__MIPSEL) || defined (__MIPSEL__) || defined (_MIPSEL) || defined (MIPSEL)
+#define __FLASHROM_LITTLE_ENDIAN__ 1
+#elif defined (__MIPSEB) || defined (__MIPSEB__) || defined (_MIPSEB) || defined (MIPSEB)
+#define __FLASHROM_BIG_ENDIAN__ 1
+#endif
+
+#elif IS_PPC
+
+/* PowerPC can be either endian. */
+#if defined (_BIG_ENDIAN) || defined (__BIG_ENDIAN__)
+#define __FLASHROM_BIG_ENDIAN__ 1
+#elif defined (_LITTLE_ENDIAN) || defined (__LITTLE_ENDIAN__)
+#define __FLASHROM_LITTLE_ENDIAN__ 1
+#endif
+
+#elif IS_ARM
+
+/* ARM can be either endian. */
+#if defined (__ARMEB__)
+#define __FLASHROM_BIG_ENDIAN__ 1
+#elif defined (__ARMEL__)
+#define __FLASHROM_LITTLE_ENDIAN__ 1
+#endif
+
+#elif IS_SPARC
+/* SPARC is big endian in general (but allows to access data in little endian too). */
+#define __FLASHROM_BIG_ENDIAN__ 1
+
+#endif /* IS_? */
+
+#if !defined (__FLASHROM_BIG_ENDIAN__) && !defined (__FLASHROM_LITTLE_ENDIAN__)
+
+/* If architecture-specific approaches fail try generic variants. First: BSD (works about everywhere). */
+#if !IS_WINDOWS
+#include <sys/param.h>
+
+#if defined (__BYTE_ORDER)
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define __FLASHROM_LITTLE_ENDIAN__
+#elif __BYTE_ORDER == __BIG_ENDIAN
+#define __FLASHROM_BIG_ENDIAN__
+#else
+#error Unknown byte order!
+#endif
+#endif /* defined __BYTE_ORDER */
+#endif /* !IS_WINDOWS */
+
+#if !defined (__FLASHROM_BIG_ENDIAN__) && !defined (__FLASHROM_LITTLE_ENDIAN__)
+
+/* Nonstandard libc-specific macros for determining endianness. */
+/* musl provides an endian.h as well... but it can not be detected from within C. */
+#if defined(__GLIBC__)
+#include <endian.h>
+#if BYTE_ORDER == LITTLE_ENDIAN
+#define __FLASHROM_LITTLE_ENDIAN__ 1
+#elif BYTE_ORDER == BIG_ENDIAN
+#define __FLASHROM_BIG_ENDIAN__ 1
+#endif
+#endif
+#endif
+
+#endif
+
+#if !defined (__FLASHROM_BIG_ENDIAN__) && !defined (__FLASHROM_LITTLE_ENDIAN__)
+#error Unable to determine endianness.
+#endif
+
 #endif /* !__PLATFORM_H__ */