diff --git a/include/os/OS.h b/include/os/OS.h
index f0b77bfc16e..52354b8278f 100644
--- a/include/os/OS.h
+++ b/include/os/OS.h
@@ -154,13 +154,13 @@ s32 OSGetResetCode(void);
 u32 OSGetSoundMode(void);
 void OSSetSoundMode(OSSoundMode mode);
 
-void OSAttention(char* msg, ...);
-void OSPanic(char* file, s32 line, char* fmt, ...);
-void OSReport(char* fmt, ...);
-void OSReport_Error(char* fmt, ...);
-void OSReport_FatalError(char* fmt, ...);
-void OSReport_System(char* fmt, ...);
-void OSReport_Warning(char* fmt, ...);
+void OSAttention(const char* msg, ...);
+void OSPanic(const char* file, s32 line, const char* fmt, ...);
+void OSReport(const char* fmt, ...);
+void OSReport_Error(const char* fmt, ...);
+void OSReport_FatalError(const char* fmt, ...);
+void OSReport_System(const char* fmt, ...);
+void OSReport_Warning(const char* fmt, ...);
 void OSReportDisable(void);
 void OSReportEnable(void);
 void OSReportForceEnableOff(void);
diff --git a/src/d/d_save/d_save.cpp b/src/d/d_save/d_save.cpp
index 79d7960f23a..0ee4b00adc4 100644
--- a/src/d/d_save/d_save.cpp
+++ b/src/d/d_save/d_save.cpp
@@ -373,7 +373,7 @@ u8 dSv_player_item_c::getItem(int item_idx, bool isComboItem) const {
                     }
                     // 合成アイテム不定＝＝＝＞%d, %d\n
                     // Uncertain combination item＝＝＝＞%d, %d\n
-                    OSReport_Error((char*)lbl_80379234 + 9, item_id_2, item_id_1);
+                    OSReport_Error(lbl_80379234 + 9, item_id_2, item_id_1);
                 }
             }
         }
diff --git a/src/m_Do/m_Do_main.cpp b/src/m_Do/m_Do_main.cpp
index 11b189dca06..757c2e9fb9b 100644
--- a/src/m_Do/m_Do_main.cpp
+++ b/src/m_Do/m_Do_main.cpp
@@ -61,7 +61,7 @@ void version_check(void) {
         return;
     }
 
-    OSReport_Error((char*)"SDK�̃o�[�W��������v���܂���B��~���܂�\n");
+    OSReport_Error("SDK�̃o�[�W��������v���܂���B��~���܂�\n");
     do {
     } while (true);
 }
diff --git a/src/m_Do/m_Do_printf.cpp b/src/m_Do/m_Do_printf.cpp
index 9e97e64e2de..bf8aaac84ee 100644
--- a/src/m_Do/m_Do_printf.cpp
+++ b/src/m_Do/m_Do_printf.cpp
@@ -17,7 +17,7 @@ void OSVAttention(const char* fmt, __va_list_struct* va_list) {
 }
 
 extern "C" {
-asm void OSAttention(char* msg, ...) {
+asm void OSAttention(const char* msg, ...) {
     nofralloc
 #include "m_Do/m_Do_printf/asm/func_80006814.s"
 }
@@ -99,32 +99,32 @@ void OSVReport(const char* format, __va_list_struct* list) {
     mDoPrintf_VReport(format, list);
 }
 
-asm void OSReport(char* fmt, ...) {
+asm void OSReport(const char* fmt, ...) {
     nofralloc
 #include "m_Do/m_Do_printf/asm/func_80006ABC.s"
 }
 
-asm void OSReport_FatalError(char* fmt, ...) {
+asm void OSReport_FatalError(const char* fmt, ...) {
     nofralloc
 #include "m_Do/m_Do_printf/asm/func_80006B3C.s"
 }
 
-asm void OSReport_Error(char* fmt, ...) {
+asm void OSReport_Error(const char* fmt, ...) {
     nofralloc
 #include "m_Do/m_Do_printf/asm/func_80006C0C.s"
 }
 
-asm void OSReport_Warning(char* fmt, ...) {
+asm void OSReport_Warning(const char* fmt, ...) {
     nofralloc
 #include "m_Do/m_Do_printf/asm/func_80006CEC.s"
 }
 
-asm void OSReport_System(char* fmt, ...) {
+asm void OSReport_System(const char* fmt, ...) {
     nofralloc
 #include "m_Do/m_Do_printf/asm/func_80006DCC.s"
 }
 
-asm void OSPanic(char* file, s32 line, char* fmt, ...) {
+asm void OSPanic(const char* file, s32 line, const char* fmt, ...) {
     nofralloc
 #include "m_Do/m_Do_printf/asm/func_80006E7C.s"
 }