Force kernel to load rootfs only for legacy SAR devices

scripts/boot_patch.sh

@@ -6,7 +6,7 @@
 # Usage: boot_patch.sh <bootimage>
 #
 # The following flags can be set in environment variables:
-# KEEPVERITY, KEEPFORCEENCRYPT, PATCHVBMETAFLAG, RECOVERYMODE, SYSTEM_ROOT
+# KEEPVERITY, KEEPFORCEENCRYPT, PATCHVBMETAFLAG, RECOVERYMODE, LEGACYSAR
 #
 # This script should be placed in a directory with the following files:
 #
@@ -73,7 +73,7 @@ fi
 [ -z $KEEPFORCEENCRYPT ] && KEEPFORCEENCRYPT=false
 [ -z $PATCHVBMETAFLAG ] && PATCHVBMETAFLAG=false
 [ -z $RECOVERYMODE ] && RECOVERYMODE=false
-[ -z $SYSTEM_ROOT ] && SYSTEM_ROOT=false
+[ -z $LEGACYSAR ] && LEGACYSAR=false
 export KEEPVERITY
 export KEEPFORCEENCRYPT
 export PATCHVBMETAFLAG
@@ -233,7 +233,7 @@ if [ -f kernel ]; then
 
   # Force kernel to load rootfs for legacy SAR devices
   # skip_initramfs -> want_initramfs
-  $SYSTEM_ROOT && ./magiskboot hexpatch kernel \
+  $LEGACYSAR && ./magiskboot hexpatch kernel \
   736B69705F696E697472616D667300 \
   77616E745F696E697472616D667300 \
   && PATCHEDKERNEL=true

scripts/util_functions.sh

@@ -312,7 +312,7 @@ mount_partitions() {
 
 # After calling this method, the following variables will be set:
 # KEEPVERITY, KEEPFORCEENCRYPT, RECOVERYMODE, PATCHVBMETAFLAG,
-# ISENCRYPTED, VBMETAEXIST
+# ISENCRYPTED, VBMETAEXIST, LEGACYSAR
 get_flags() {
   getvar KEEPVERITY
   getvar KEEPFORCEENCRYPT
@@ -350,6 +350,15 @@ get_flags() {
     fi
   fi
   [ -z $RECOVERYMODE ] && RECOVERYMODE=false
+  local IS_DYNAMIC=false
+  grep -q 'androidboot.super_partition' /proc/cmdline && IS_DYNAMIC=true
+  [ -b "/dev/block/by-name/super" ] && IS_DYNAMIC=true
+  if $SYSTEM_ROOT && ! $IS_DYNAMIC; then
+    LEGACYSAR=true
+    ui_print "- legacy SAR, force kernel to load rootfs"
+  else
+    LEGACYSAR=false
+  fi
 }
 
 find_boot_image() {