diff --git a/kernel/ps4_signal.pas b/kernel/ps4_signal.pas
index e57e9bb8..7667202b 100644
--- a/kernel/ps4_signal.pas
+++ b/kernel/ps4_signal.pas
@@ -56,6 +56,7 @@ end;
 function ps4_is_signal_return(param:PQWORD):Integer; SysV_ABI_CDecl;
 begin
  Result:=1;
+ if ptruint(param)<4*1024 then Exit;
 
  if (param[0]<>$48006a40247c8d48) or
     (param[1]<>$050f000001a1c0c7) or
diff --git a/ps4_elf.pas b/ps4_elf.pas
index b9eebcf3..edbb1c42 100644
--- a/ps4_elf.pas
+++ b/ps4_elf.pas
@@ -2907,7 +2907,7 @@ begin
 
  //OpenOrbis relies on the fact that besides %rdi and %rsp also link to StartupParams, a very strange thing
  asm
-  xor %esi,%esi
+  xor %rsi,%rsi
   lea StartupParams,%rdi
   mov %rdi,%rsp
   jmp P