diff --git a/src/dynarmic/backend/x64/a32_emit_x64_memory.cpp b/src/dynarmic/backend/x64/a32_emit_x64_memory.cpp
index 35588758..804a114a 100644
--- a/src/dynarmic/backend/x64/a32_emit_x64_memory.cpp
+++ b/src/dynarmic/backend/x64/a32_emit_x64_memory.cpp
@@ -243,6 +243,7 @@ void A32EmitX64::EmitMemoryRead(A32EmitContext& ctx, IR::Inst* inst) {
         // Neither fastmem nor page table: Use callbacks
         ctx.reg_alloc.HostCall(inst, {}, args[0]);
         Devirtualize<callback>(conf.callbacks).EmitCall(code);
+        code.ZeroExtendFrom(bitsize, code.ABI_RETURN);
         return;
     }
 
@@ -386,6 +387,7 @@ void A32EmitX64::ExclusiveReadMemory(A32EmitContext& ctx, IR::Inst* inst) {
                 return (conf.callbacks->*callback)(vaddr);
             });
         });
+    code.ZeroExtendFrom(bitsize, code.ABI_RETURN);
 }
 
 template<size_t bitsize, auto callback>
diff --git a/src/dynarmic/backend/x64/a64_emit_x64_memory.cpp b/src/dynarmic/backend/x64/a64_emit_x64_memory.cpp
index d86bdf3f..29aeaf01 100644
--- a/src/dynarmic/backend/x64/a64_emit_x64_memory.cpp
+++ b/src/dynarmic/backend/x64/a64_emit_x64_memory.cpp
@@ -406,6 +406,7 @@ void A64EmitX64::EmitMemoryRead(A64EmitContext& ctx, IR::Inst* inst) {
         } else {
             ctx.reg_alloc.HostCall(inst, {}, args[0]);
             Devirtualize<callback>(conf.callbacks).EmitCall(code);
+            code.ZeroExtendFrom(bitsize, code.ABI_RETURN);
         }
         return;
     }
@@ -574,6 +575,7 @@ void A64EmitX64::EmitExclusiveReadMemory(A64EmitContext& ctx, IR::Inst* inst) {
                     return (conf.callbacks->*callback)(vaddr);
                 });
             });
+        code.ZeroExtendFrom(bitsize, code.ABI_RETURN);
     } else {
         const Xbyak::Xmm result = ctx.reg_alloc.ScratchXmm();
         ctx.reg_alloc.Use(args[0], ABI_PARAM2);
diff --git a/src/dynarmic/backend/x64/emit_x64_sm4.cpp b/src/dynarmic/backend/x64/emit_x64_sm4.cpp
index bee51a80..b084a92f 100644
--- a/src/dynarmic/backend/x64/emit_x64_sm4.cpp
+++ b/src/dynarmic/backend/x64/emit_x64_sm4.cpp
@@ -15,6 +15,7 @@ void EmitX64::EmitSM4AccessSubstitutionBox(EmitContext& ctx, IR::Inst* inst) {
 
     ctx.reg_alloc.HostCall(inst, args[0]);
     code.CallFunction(&Common::Crypto::SM4::AccessSubstitutionBox);
+    code.movzx(code.ABI_RETURN.cvt32(), code.ABI_RETURN.cvt8());
 }
 
 }  // namespace Dynarmic::Backend::X64