From 594e54df976beb4fb9f4b761c49357061c28fcb0 Mon Sep 17 00:00:00 2001
From: Natalia Portillo <claunia@claunia.com>
Date: Sun, 16 May 2021 07:14:16 +0100
Subject: [PATCH] Correct protection error when accessing system base in Atari
 ST.

---
 setter/src/atarist/os.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/setter/src/atarist/os.c b/setter/src/atarist/os.c
index 09102ab..01dd101 100644
--- a/setter/src/atarist/os.c
+++ b/setter/src/atarist/os.c
@@ -39,7 +39,7 @@ Copyright (C) 2011-2021 Natalia Portillo
 
 void GetOsInfo()
 {
-    OSHEADER*             osHeader = (OSHEADER*)_sysbase;
+    OSHEADER*             osHeader;
     unsigned short        version;
     long**                cookieJar = _p_cookies;
     long                  cookie    = 0;
@@ -48,6 +48,15 @@ void GetOsInfo()
     struct _stemu_vars*   stemu_vars;
     struct _tos2win_vars* tos2win_vars;
     MAGX_COOKIE*          magic_vars;
+    int32_t               savessp;
+
+    // Retrieve the OS data in Supervisor mode
+    savessp  = Super(0L);
+    osHeader = *((OSHEADER**)_sysbase);
+    Super((void*)savessp);
+
+    // Due to old AHDI bug
+    osHeader = osHeader->os_beg;
 
     version = Sversion();