diff --git a/include/d/actor/d_a_obj_stone.h b/include/d/actor/d_a_obj_stone.h
index bad3bb5d611..b5f4da8c391 100644
--- a/include/d/actor/d_a_obj_stone.h
+++ b/include/d/actor/d_a_obj_stone.h
@@ -81,7 +81,7 @@ private:
     /* 0x094E */ bool mIsInWater;
     /* 0x094F */ u8 field_0x094f;
     /* 0x0950 */ u8 field_0x0950;
-    /* 0x0951 */ u8 field_0x0951;
+    /* 0x0951 */ bool field_0x0951;
     /* 0x0954 */ u32 field_0x0954;
     /* 0x0954 */ u32 field_0x0958;
     /* 0x0954 */ u32 field_0x095c;
diff --git a/src/d/actor/d_a_mg_fish.cpp b/src/d/actor/d_a_mg_fish.cpp
index c5ed70b7402..b23eeba7096 100644
--- a/src/d/actor/d_a_mg_fish.cpp
+++ b/src/d/actor/d_a_mg_fish.cpp
@@ -1039,7 +1039,7 @@ static void mf_away(mg_fish_class* i_this) {
         break;
     case 5:
         if (i_this->mGedouKind < GEDOU_KIND_BG) {
-            if ((i_this->mAcch.m_flags & (1 << 4)) != 0) {
+            if (i_this->mAcch.ChkWallHit()) {
                 if (i_this->field_0x624[1] == 0) {
                     i_this->mActionPhase = 0;
                     i_this->field_0x624[1] = 40;
@@ -1982,7 +1982,7 @@ static void mf_jump(mg_fish_class* i_this) {
         i_this->mMaxStep = 0x600;
         i_this->actor.current.pos += i_this->field_0x5e0;
         i_this->field_0x5e0.y = i_this->field_0x5e0.y - 2.0f;
-        if ((i_this->mAcch.m_flags & 0x20) != 0) {
+        if (i_this->mAcch.ChkGroundHit()) {
             i_this->actor.current.pos.x = i_this->actor.old.pos.x;
             i_this->actor.current.pos.y = i_this->actor.old.pos.y;
             i_this->actor.current.pos.z = i_this->actor.old.pos.z;
diff --git a/src/d/actor/d_a_obj_lbox.cpp b/src/d/actor/d_a_obj_lbox.cpp
index 8f23621e2cb..7f6b5e44a15 100644
--- a/src/d/actor/d_a_obj_lbox.cpp
+++ b/src/d/actor/d_a_obj_lbox.cpp
@@ -52,7 +52,7 @@ static void action(obj_lbox_class* i_this) {
             i_this->speed.y -= 0.1f;
         }
         i_this->current.pos.y += i_this->speed.y;
-        if (i_this->mObjAcch.m_flags & 0x20) {
+        if (i_this->mObjAcch.ChkGroundHit()) {
             dComIfGp_getVibration().StartShock(5, 15, cXyz(0.0f, 1.0f, 0.0f));
             fopAcM_seStart(i_this, Z2SE_EN_FM_FOOTNOTE, 0);
             i_this->field_0x57a = 2;
diff --git a/src/d/actor/d_a_obj_stone.cpp b/src/d/actor/d_a_obj_stone.cpp
index 36ff9973b66..62a384c52dd 100644
--- a/src/d/actor/d_a_obj_stone.cpp
+++ b/src/d/actor/d_a_obj_stone.cpp
@@ -318,11 +318,11 @@ void daObjStone_c::mode_proc_call() {
     if (mCollider.ChkAtHit()) {
         init_modeBreak();
     }
-    bool isGroundLanding = mChkObj.ChkGroundLanding() != 0;
-    u32 isWallhit = mChkObj.m_flags & dBgS_Acch::WALL_HIT;
-    bool isGroundHit = mChkObj.ChkGroundHit() != 0;
-    bool isWaterHit = mChkObj.ChkWaterHit() != 0;
-    bool isWaterIn = mChkObj.ChkWaterIn() != 0;
+    bool isGroundLanding = mChkObj.ChkGroundLanding();
+    u32 isWallhit = mChkObj.ChkWallHit();
+    bool isGroundHit = mChkObj.ChkGroundHit();
+    bool isWaterHit = mChkObj.ChkWaterHit();
+    bool isWaterIn = mChkObj.ChkWaterIn();
     if (field_0x0907 == 1) {
         if (isGroundLanding && !isWaterIn) {
             speed.x = speedF * cM_ssin(current.angle.y);
@@ -336,7 +336,7 @@ void daObjStone_c::mode_proc_call() {
             speedF = speed.absXZ();
             current.angle.y = cM_atan2s(speed.x, speed.z);
         } else {
-            if (isWallhit && field_0x0951 == 0 && isWaterIn) {
+            if (isWallhit && !field_0x0951 && isWaterIn) {
                 speed.x = speedF * cM_ssin(current.angle.y);
                 speed.z = speedF * cM_scos(current.angle.y);
                 speed.y = mLastSpeedY;
@@ -489,7 +489,7 @@ void daObjStone_c::mode_proc_call() {
     }
     (this->*(l_func[field_0x0907]))();
     CrrPos();
-    field_0x0951 = isWallhit != 0;
+    field_0x0951 = isWallhit;
 }
 
 void daObjStone_c::init_modePutWait() {
diff --git a/src/d/actor/d_a_obj_zrTuraraRock.cpp b/src/d/actor/d_a_obj_zrTuraraRock.cpp
index 538227d5395..98eb4d4ace4 100644
--- a/src/d/actor/d_a_obj_zrTuraraRock.cpp
+++ b/src/d/actor/d_a_obj_zrTuraraRock.cpp
@@ -125,8 +125,8 @@ void daZrTuraRc_c::modeDrop() {
 }
 
 void daZrTuraRc_c::bgCheck() {
-    // this should be ChkGroundHit but that doesn't match
-    if (mAcch.m_flags >> 5 & 1) {
+    bool r31 = mAcch.ChkGroundHit();
+    if (r31) {
         init_modeDropEnd();
     }
 }