diff --git a/build.py b/build.py
index bf5c917ec..20d0dd953 100755
--- a/build.py
+++ b/build.py
@@ -104,17 +104,35 @@ def build_binary(args):
 	os.utime(os.path.join('native', 'jni', 'include', 'logging.h'))
 
 	# Basic flags
-	flags = 'MAGISK_VERSION=\"{}\" MAGISK_VER_CODE={} MAGISK_DEBUG={}'.format(config['version'], config['versionCode'],
+	base_flags = 'MAGISK_VERSION=\"{}\" MAGISK_VER_CODE={} MAGISK_DEBUG={}'.format(config['version'], config['versionCode'],
 		'' if args.release else '-DMAGISK_DEBUG')
 
 	if 'magisk' in args.target:
 		# Magisk is special case as it is a dependency of magiskinit
-		proc = subprocess.run('{} -C native {} B_MAGISK=true -j{}'.format(ndk_build, flags, cpu_count), shell=True)
+		proc = subprocess.run('{} -C native {} B_MAGISK=1 -j{}'.format(ndk_build, base_flags, cpu_count), shell=True)
 		if proc.returncode != 0:
 			error('Build Magisk binary failed!')
 		collect_binary()
 
-	non_magisk = False
+	old_platform = False
+	flags = base_flags
+
+	if 'busybox' in args.target:
+		flags += ' B_BB=1'
+		old_platform = True
+
+	if 'b64xz' in args.target:
+		flags += ' B_BXZ=1'
+		old_platform = True
+
+	if old_platform:
+		proc = subprocess.run('{} -C native OLD_PLAT=1 {} -j{}'.format(ndk_build, flags, cpu_count), shell=True)
+		if proc.returncode != 0:
+			error('Build binaries failed!')
+		collect_binary()
+
+	other = False
+	flags = base_flags
 
 	if 'magiskinit' in args.target:
 		# We need to create dump.h beforehand
@@ -127,22 +145,14 @@ def build_binary(args):
 					dump.write('const uint8_t magisk_dump[] = "')
 					dump.write(''.join("\\x{:02X}".format(c) for c in lzma.compress(bin.read(), preset=9)))
 					dump.write('";\n')
-		flags += ' B_INIT=true'
-		non_magisk = True
+		flags += ' B_INIT=1'
+		other = True
 
 	if 'magiskboot' in args.target:
-		flags += ' B_BOOT=true'
-		non_magisk = True
+		flags += ' B_BOOT=1'
+		other = True
 
-	if 'busybox' in args.target:
-		flags += ' B_BB=true'
-		non_magisk = True
-
-	if 'b64xz' in args.target:
-		flags += ' B_BXZ=true'
-		non_magisk = True
-
-	if non_magisk:
+	if other:
 		proc = subprocess.run('{} -C native {} -j{}'.format(ndk_build, flags, cpu_count), shell=True)
 		if proc.returncode != 0:
 			error('Build binaries failed!')
@@ -369,7 +379,7 @@ def cleanup(args):
 
 	if 'binary' in args.target:
 		header('* Cleaning binaries')
-		subprocess.run(ndk_build + ' -C native B_MAGISK=true B_INIT=true B_BOOT=true B_BXZ=true B_BB=true clean', shell=True)
+		subprocess.run(ndk_build + ' -C native B_MAGISK=1 B_INIT=1 B_BOOT=1 B_BXZ=1 B_BB=1 clean', shell=True)
 		shutil.rmtree(os.path.join('native', 'out'), ignore_errors=True)
 
 	if 'java' in args.target:
diff --git a/native/build.gradle b/native/build.gradle
index e0f3c8eb5..95b2a51da 100644
--- a/native/build.gradle
+++ b/native/build.gradle
@@ -14,7 +14,7 @@ android {
         externalNativeBuild {
             ndkBuild {
                 // Pass arguments to ndk-build.
-                arguments('B_MAGISK=true', 'B_INIT=true', 'B_BOOT=true', 'MAGISK_VERSION=debug',
+                arguments('B_MAGISK=1', 'B_INIT=1', 'B_BOOT=1', 'MAGISK_VERSION=debug',
                         'MAGISK_VER_CODE=99999', 'MAGISK_DEBUG=-DMAGISK_DEBUG')
             }
         }
diff --git a/native/jni/Android.mk b/native/jni/Android.mk
index 2532efa2c..90d7bc63e 100644
--- a/native/jni/Android.mk
+++ b/native/jni/Android.mk
@@ -57,8 +57,7 @@ LOCAL_SRC_FILES := \
 	su/su_socket.c \
 	$(UTIL_SRC)
 
-LOCAL_CFLAGS := -DIS_DAEMON -DSELINUX ${MAGISK_DEBUG} \
-	-DMAGISK_VERSION="${MAGISK_VERSION}" -DMAGISK_VER_CODE=${MAGISK_VER_CODE} 
+LOCAL_CFLAGS := -DIS_DAEMON -DSELINUX
 LOCAL_LDLIBS := -llog
 include $(BUILD_EXECUTABLE)
 
diff --git a/native/jni/Application.mk b/native/jni/Application.mk
index 6969fbdf7..df3c77e35 100644
--- a/native/jni/Application.mk
+++ b/native/jni/Application.mk
@@ -1,5 +1,10 @@
 APP_ABI := x86 armeabi-v7a
-APP_PLATFORM := android-21
-APP_CFLAGS := -std=gnu99
+APP_CFLAGS := -std=gnu99 ${MAGISK_DEBUG} \
+	-DMAGISK_VERSION="${MAGISK_VERSION}" -DMAGISK_VER_CODE=${MAGISK_VER_CODE} 
 APP_CPPFLAGS := -std=c++11
 APP_SHORT_COMMANDS := true
+ifdef OLD_PLAT
+APP_PLATFORM := android-9
+else
+APP_PLATFORM := android-21	
+endif
diff --git a/native/jni/external/Android.mk b/native/jni/external/Android.mk
index daefac0cd..ccd03f54e 100644
--- a/native/jni/external/Android.mk
+++ b/native/jni/external/Android.mk
@@ -175,7 +175,7 @@ LOCAL_SRC_FILES := \
 	xz/src/liblzma/simple/simple_encoder.c \
 	xz/src/liblzma/simple/sparc.c \
 	xz/src/liblzma/simple/x86.c
-LOCAL_CFLAGS += -DHAVE_CONFIG_H -std=c99
+LOCAL_CFLAGS += -DHAVE_CONFIG_H -Wno-implicit-function-declaration
 include $(BUILD_STATIC_LIBRARY)
 
 # libsepol.a
diff --git a/native/jni/external/busybox b/native/jni/external/busybox
index 4f5bf4ad8..869ebbfa9 160000
--- a/native/jni/external/busybox
+++ b/native/jni/external/busybox
@@ -1 +1 @@
-Subproject commit 4f5bf4ad8361c46441db19bd61605d0de324f19e
+Subproject commit 869ebbfa97d9b47b2707adb10a01d1bfacd52191