diff --git a/src/Makefile b/src/Makefile
index 79340a96..224d21e7 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -233,7 +233,7 @@ TARGET_ALDFLAGS= $(LDOPTIONS) $(TARGET_XLDFLAGS) $(TARGET_FLAGS) $(TARGET_LDFLAG
 TARGET_ASHLDFLAGS= $(LDOPTIONS) $(TARGET_XSHLDFLAGS) $(TARGET_FLAGS) $(TARGET_SHLDFLAGS)
 TARGET_ALIBS= $(TARGET_XLIBS) $(LIBS) $(TARGET_LIBS)
 
-TARGET_TESTARCH=$(shell $(TARGET_CC) $(TARGET_TCFLAGS) -E lj_arch.h -dM)
+TARGET_TESTARCH:=$(shell $(TARGET_CC) $(TARGET_TCFLAGS) -E lj_arch.h -dM)
 ifneq (,$(findstring LJ_TARGET_X64 ,$(TARGET_TESTARCH)))
   TARGET_LJARCH= x64
 else
diff --git a/src/lj_arch.h b/src/lj_arch.h
index 6e22b1b2..3e920f2a 100644
--- a/src/lj_arch.h
+++ b/src/lj_arch.h
@@ -66,7 +66,7 @@
 #elif defined(__mips__) || defined(__mips) || defined(__MIPS__) || defined(__MIPS)
 #define LUAJIT_TARGET	LUAJIT_ARCH_MIPS32
 #else
-#error "No support for this architecture (yet)"
+#error "Architecture not supported (in this version), see: https://luajit.org/status.html#architectures"
 #endif
 
 #endif
@@ -237,7 +237,7 @@
 #define LJ_TARGET_UNIFYROT	2	/* Want only IR_BROR. */
 #define LJ_ARCH_NUMMODE		LJ_NUMMODE_DUAL
 
-#if __ARM_ARCH == 8 || __ARM_ARCH_8__ || __ARM_ARCH_8A__
+#if __ARM_ARCH >= 8 || __ARM_ARCH_8__ || __ARM_ARCH_8A__
 #define LJ_ARCH_VERSION		80
 #elif __ARM_ARCH == 7 || __ARM_ARCH_7__ || __ARM_ARCH_7A__ || __ARM_ARCH_7R__ || __ARM_ARCH_7S__ || __ARM_ARCH_7VE__
 #define LJ_ARCH_VERSION		70
@@ -331,6 +331,7 @@
 #define LJ_ARCH_NOFFI		1
 #elif LJ_ARCH_BITS == 64
 #error "No support for PPC64"
+#undef LJ_TARGET_PPC
 #endif
 
 #if _ARCH_PWR7
@@ -490,36 +491,45 @@
 #elif LJ_TARGET_ARM
 #if defined(__ARMEB__)
 #error "No support for big-endian ARM"
+#undef LJ_TARGET_ARM
 #endif
 #if __ARM_ARCH_6M__ || __ARM_ARCH_7M__ || __ARM_ARCH_7EM__
 #error "No support for Cortex-M CPUs"
+#undef LJ_TARGET_ARM
 #endif
 #if !(__ARM_EABI__ || LJ_TARGET_IOS)
 #error "Only ARM EABI or iOS 3.0+ ABI is supported"
+#undef LJ_TARGET_ARM
 #endif
 #elif LJ_TARGET_ARM64
 #if defined(_ILP32)
 #error "No support for ILP32 model on ARM64"
+#undef LJ_TARGET_ARM64
 #endif
 #elif LJ_TARGET_PPC
 #if defined(_LITTLE_ENDIAN) && (!defined(_BYTE_ORDER) || (_BYTE_ORDER == _LITTLE_ENDIAN))
 #error "No support for little-endian PPC32"
+#undef LJ_TARGET_PPC
 #endif
 #if defined(__NO_FPRS__) && !defined(_SOFT_FLOAT)
-#error "No support for PPC/e500 anymore (use LuaJIT 2.0)"
+#error "No support for PPC/e500, use LuaJIT 2.0"
+#undef LJ_TARGET_PPC
 #endif
 #elif LJ_TARGET_MIPS32
 #if !((defined(_MIPS_SIM_ABI32) && _MIPS_SIM == _MIPS_SIM_ABI32) || (defined(_ABIO32) && _MIPS_SIM == _ABIO32))
 #error "Only o32 ABI supported for MIPS32"
+#undef LJ_TARGET_MIPS
 #endif
 #if LJ_TARGET_MIPSR6
 /* Not that useful, since most available r6 CPUs are 64 bit. */
 #error "No support for MIPS32R6"
+#undef LJ_TARGET_MIPS
 #endif
 #elif LJ_TARGET_MIPS64
 #if !((defined(_MIPS_SIM_ABI64) && _MIPS_SIM == _MIPS_SIM_ABI64) || (defined(_ABI64) && _MIPS_SIM == _ABI64))
 /* MIPS32ON64 aka n32 ABI support might be desirable, but difficult. */
 #error "Only n64 ABI supported for MIPS64"
+#undef LJ_TARGET_MIPS
 #endif
 #endif
 #endif