diff --git a/scripts/generate_BUFSIZ.sh b/scripts/generate_BUFSIZ.sh
index 1914fa0..8aa0174 100755
--- a/scripts/generate_BUFSIZ.sh
+++ b/scripts/generate_BUFSIZ.sh
@@ -7,11 +7,16 @@
 
 debug=false
 
+postcompile=false
+test x"$1" = x"--post" && { postcompile=true; shift; }
+
 common_bufsiz_h=$1
 
 test x"$NM" = x"" && NM="${CONFIG_CROSS_COMPILER_PREFIX}nm"
 test x"$CC" = x"" && CC="${CONFIG_CROSS_COMPILER_PREFIX}gcc"
 
+exitcmd="exit 0"
+
 regenerate() {
 	cat >"$1.$$"
 	test -f "$1" && diff "$1.$$" "$1" >/dev/null && rm "$1.$$" && return
@@ -19,99 +24,130 @@
 }
 
 generate_std_and_exit() {
-	$debug && echo "Default: bb_common_bufsiz1[] in bss"
+	$debug && echo "Configuring: bb_common_bufsiz1[] in bss"
 	{
 	echo "enum { COMMON_BUFSIZE = 1024 };"
 	echo "extern char bb_common_bufsiz1[];"
 	echo "#define setup_common_bufsiz() ((void)0)"
 	} | regenerate "$common_bufsiz_h"
-	exit 0
+	echo "std" >"$common_bufsiz_h.method"
+	$exitcmd
 }
 
-# User does not want any funky stuff?
-test x"$CONFIG_FEATURE_USE_BSS_TAIL" = x"y" || generate_std_and_exit
-
-test -f busybox_unstripped || {
-	# We did not try anything yet
-	$debug && echo "Will try to fit bb_common_bufsiz1[] into _end[]"
+generate_big_and_exit() {
+	$debug && echo "Configuring: bb_common_bufsiz1[] in _end[], COMMON_BUFSIZE = $1"
 	{
-	echo "enum { COMMON_BUFSIZE = 1024 };"
+	echo "enum { COMMON_BUFSIZE = $1 };"
 	echo "extern char _end[]; /* linker-provided label */"
 	echo "#define bb_common_bufsiz1 _end"
 	echo "#define setup_common_bufsiz() ((void)0)"
 	} | regenerate "$common_bufsiz_h"
-	echo 1024 >"$common_bufsiz_h.BUFSIZE"
-	exit 0
+	echo "$2" >"$common_bufsiz_h.method"
+	$exitcmd
 }
 
-# Get _end address
-END=`$NM busybox_unstripped | grep ' . _end$'| cut -d' ' -f1`
-test x"$END" = x"" && generate_std_and_exit
-$debug && echo "END:0x$END $((0x$END))"
-END=$((0x$END))
+generate_1k_and_exit() {
+	generate_big_and_exit 1024 "1k"
+}
 
-# Get PAGE_SIZE
-echo "\
-#include <sys/user.h>
-#if defined(PAGE_SIZE) && PAGE_SIZE > 0
-char page_size[PAGE_SIZE];
-#else
-char page_size[1];
-#endif
-" >page_size_$$.c
-$CC -c "page_size_$$.c" || generate_std_and_exit
-PAGE_SIZE=`$NM --size-sort "page_size_$$.o" | cut -d' ' -f1`
-rm "page_size_$$.c" "page_size_$$.o"
-test x"$PAGE_SIZE" = x"" && generate_std_and_exit
-$debug && echo "PAGE_SIZE:0x$PAGE_SIZE $((0x$PAGE_SIZE))"
-PAGE_SIZE=$((0x$PAGE_SIZE))
-test $PAGE_SIZE -lt 1024 && generate_std_and_exit
 
-# How much space between _end[] and next page?
-PAGE_MASK=$((PAGE_SIZE-1))
-REM=$(( (-END) & PAGE_MASK ))
-$debug && echo "REM:$REM"
-
-if test $REM -lt 1024; then
-	# _end[] has no enough space for bb_common_bufsiz1[],
-	# users will need to malloc it.
+generate_malloc_and_exit() {
+	$debug && echo "Configuring: bb_common_bufsiz1[] is malloced"
 	{
 	echo "enum { COMMON_BUFSIZE = 1024 };"
 	echo "extern char *const bb_common_bufsiz1;"
 	echo "void setup_common_bufsiz(void);"
 	} | regenerate "$common_bufsiz_h"
-	# Check that we aren't left with a buggy binary:
-	if test -f "$common_bufsiz_h.BUFSIZE"; then
-		rm "$common_bufsiz_h.BUFSIZE"
-		echo "Warning! Space in _end[] is too small ($REM bytes)!"
-		echo "Rerun make to build a binary which doesn't use it!"
-		exit 1
+	echo "malloc" >"$common_bufsiz_h.method"
+	$exitcmd
+}
+
+# User does not want any funky stuff?
+test x"$CONFIG_FEATURE_USE_BSS_TAIL" = x"y" || generate_std_and_exit
+
+# The script is run two times: before compilation, when it needs to
+# (re)generate $common_bufsiz_h, and directly after successful build,
+# when it needs to assess whether the build is ok to use at all (not buggy),
+# and (re)generate $common_bufsiz_h for a future build.
+
+if $postcompile; then
+	# Postcompile needs to create/delete OK/FAIL files
+
+	test -f busybox_unstripped || exit 1
+	test -f "$common_bufsiz_h.method" || exit 1
+
+	# How the build was done?
+	method=`cat -- "$common_bufsiz_h.method"`
+
+	# Get _end address
+	END=`$NM busybox_unstripped | grep ' . _end$'| cut -d' ' -f1`
+	test x"$END" = x"" && generate_std_and_exit
+	$debug && echo "END:0x$END $((0x$END))"
+	END=$((0x$END))
+
+	# Get PAGE_SIZE
+	{
+	echo "#include <sys/user.h>"
+	echo "#if defined(PAGE_SIZE) && PAGE_SIZE > 0"
+	echo "char page_size[PAGE_SIZE];"
+	echo "#endif"
+	} >page_size_$$.c
+	$CC -c "page_size_$$.c" || exit 1
+	PAGE_SIZE=`$NM --size-sort "page_size_$$.o" | cut -d' ' -f1`
+	rm "page_size_$$.c" "page_size_$$.o"
+	test x"$PAGE_SIZE" = x"" && exit 1
+	$debug && echo "PAGE_SIZE:0x$PAGE_SIZE $((0x$PAGE_SIZE))"
+	PAGE_SIZE=$((0x$PAGE_SIZE))
+	test $PAGE_SIZE -lt 512 && exit 1
+
+	# How much space between _end[] and next page?
+	PAGE_MASK=$((PAGE_SIZE-1))
+	COMMON_BUFSIZE=$(( (-END) & PAGE_MASK ))
+	echo "COMMON_BUFSIZE = $COMMON_BUFSIZE bytes"
+
+	if test x"$method" = x"1k"; then
+		if test $COMMON_BUFSIZE -lt 1024; then
+			# _end[] has no enough space for bb_common_bufsiz1[]
+			rm -- "$common_bufsiz_h.1k.OK" 2>/dev/null
+			{ md5sum <.config | cut -d' ' -f1; stat -c "%Y" .config; } >"$common_bufsiz_h.1k.FAIL"
+			echo "Warning! Space in _end[] is too small ($COMMON_BUFSIZE bytes)!"
+			echo "Rerun make to build a binary which doesn't use it!"
+			rm busybox_unstripped
+			exitcmd="exit 1"
+		else
+			rm -- "$common_bufsiz_h.1k.FAIL" 2>/dev/null
+			echo $COMMON_BUFSIZE >"$common_bufsiz_h.1k.OK"
+			test $COMMON_BUFSIZE -gt $((1024+32)) && echo "Rerun make to use larger COMMON_BUFSIZE"
+		fi
 	fi
-	echo "COMMON_BUFSIZE = 1024 bytes, the buffer will be malloced"
-	exit 0
 fi
 
-# _end[] has REM bytes for bb_common_bufsiz1[]
-OLD=1024
-test -f "$common_bufsiz_h.BUFSIZE" && OLD=`cat "$common_bufsiz_h.BUFSIZE"`
-$debug && echo "OLD:$OLD"
-{
-echo "enum { COMMON_BUFSIZE = $REM };"
-echo "extern char _end[]; /* linker-provided label */"
-echo "#define bb_common_bufsiz1 _end"
-echo "#define setup_common_bufsiz() ((void)0)"
-} | regenerate "$common_bufsiz_h"
-echo $REM >"$common_bufsiz_h.BUFSIZE"
+# Based on past success/fail of 1k build, decide next build type
 
-# Check that code did not grow too much and thus _end[] did not shrink:
-if test $OLD -gt $REM; then
-	echo "Warning! Space in _end[] has decreased from $OLD to $REM bytes!"
-	echo "Rerun make!"
-	exit 1
+if test -f "$common_bufsiz_h.1k.OK"; then
+	# Previous build succeeded fitting 1k into _end[].
+	# Try bigger COMMON_BUFSIZE if possible.
+	COMMON_BUFSIZE=`cat -- "$common_bufsiz_h.1k.OK"`
+	# Round down a bit
+	COMMON_BUFSIZE=$(( (COMMON_BUFSIZE-32) & 0xfffffe0 ))
+	COMMON_BUFSIZE=$(( COMMON_BUFSIZE < 1024 ? 1024 : COMMON_BUFSIZE ))
+	test $COMMON_BUFSIZE = 1024 && generate_1k_and_exit
+	generate_big_and_exit $COMMON_BUFSIZE "big"
 fi
-
-if test $OLD != $REM; then
-	echo "Space in _end[] is $REM bytes. Rerun make to use larger COMMON_BUFSIZE."
-else
-	echo "COMMON_BUFSIZE = $REM bytes"
+if test -f "$common_bufsiz_h.1k.FAIL"; then
+	# Previous build FAILED to fit 1k into _end[].
+	# Was it with same .config?
+	oldcfg=`cat -- "$common_bufsiz_h.1k.FAIL"`
+	curcfg=`md5sum <.config | cut -d' ' -f1; stat -c "%Y" .config`
+	# If yes, then build a "malloced" version
+	if test x"$oldcfg" = x"$curcfg"; then
+		echo "Will not try 1k build, it failed before. Touch .config to override"
+		generate_malloc_and_exit
+	fi
+	# else: try 1k version
+	echo "New .config, will try 1k build"
+	rm -- "$common_bufsiz_h.1k.FAIL"
+	generate_1k_and_exit
 fi
+# There was no 1k build yet. Try it.
+generate_1k_and_exit