diff --git a/include/simdjson.h b/include/simdjson.h
index a52e9ce00..7dc03d09f 100644
--- a/include/simdjson.h
+++ b/include/simdjson.h
@@ -72,6 +72,15 @@ SIMDJSON_DISABLE_UNDESIRED_WARNINGS
 #include "simdjson/internal/tape_ref-inl.h"
 #include "simdjson/dom/serialization-inl.h"
 
+// Implementation-internal files (must be included before the implementations themselves, to keep
+// amalgamation working--otherwise, the first time a file is included, it might be put inside the
+// #ifdef SIMDJSON_IMPLEMENTATION_ARM64/FALLBACK/etc., which means the other implementations can't
+// compile unless that implementation is turned on).
+#include "simdjson/internal/isadetection.h"
+#include "simdjson/internal/jsoncharutils_tables.h"
+#include "simdjson/internal/numberparsing_tables.h"
+#include "simdjson/internal/simdprune_tables.h"
+
 // Implementations
 #include "simdjson/arm64.h"
 #include "simdjson/fallback.h"
diff --git a/singleheader/amalgamate.sh b/singleheader/amalgamate.sh
index 5dd8c5916..065bd091f 100755
--- a/singleheader/amalgamate.sh
+++ b/singleheader/amalgamate.sh
@@ -46,7 +46,15 @@ function doinclude()
     file=$1
     line="${@:2}"
     if [ -f $AMALGAMATE_INCLUDE_PATH/$file ]; then
-        if [[ ! " ${found_includes[@]} " =~ " ${file} " ]]; then
+        # generic includes are included multiple times
+        if [[ "${file}" == *'generic/'*'.h' ]]; then
+            dofile $AMALGAMATE_INCLUDE_PATH $file
+        # begin/end_implementation are also included multiple times
+        elif [[ "${file}" == *'/begin.h' ]]; then
+            dofile $AMALGAMATE_INCLUDE_PATH $file
+        elif [[ "${file}" == *'/end.h' ]]; then
+            dofile $AMALGAMATE_INCLUDE_PATH $file
+        elif [[ ! " ${found_includes[@]} " =~ " ${file} " ]]; then
             found_includes+=("$file")
             dofile $AMALGAMATE_INCLUDE_PATH $file
         fi
@@ -54,11 +62,6 @@ function doinclude()
         # generic includes are included multiple times
         if [[ "${file}" == *'generic/'*'.h' ]]; then
             dofile $AMALGAMATE_SOURCE_PATH $file
-        # begin/end_implementation are also included multiple times
-        elif [[ "${file}" == *'begin_implementation.h' ]]; then
-            dofile $AMALGAMATE_SOURCE_PATH $file
-        elif [[ "${file}" == *'end_implementation.h' ]]; then
-            dofile $AMALGAMATE_SOURCE_PATH $file
         elif [[ ! " ${found_includes[@]} " =~ " ${file} " ]]; then
             found_includes+=("$file")
             dofile $AMALGAMATE_SOURCE_PATH $file