diff --git a/src/Debug/debugger.cpp b/src/Debug/debugger.cpp
index 94edf40b..50d3c8d1 100644
--- a/src/Debug/debugger.cpp
+++ b/src/Debug/debugger.cpp
@@ -974,14 +974,16 @@ void Debugger::inspect(Module *m, const uint16_t sizeStateArray,
                 this->channel->write("%s", addComma ? "," : "");
                 this->channel->write(R"("overrides": [)");
                 bool comma = false;
-                for (auto key : overrides) {
-                    for (auto argResult : key.second) {
-                        this->channel->write("%s", comma ? ", " : "");
-                        this->channel->write(
-                            R"({"fidx": %d, "arg": %d, "return_value": %d})",
-                            key.first, argResult.first, argResult.second);
-                        comma = true;
+                for (const auto &[key, return_value] : overrides) {
+                    this->channel->write("%s", comma ? ", " : "");
+                    const uint32_t fidx = key[key.size() - 1];
+                    this->channel->write(R"({"fidx": %d, "args": [)", fidx);
+                    for (uint32_t i = 0; i < key.size() - 1; i++) {
+                        this->channel->write("%s%d", i > 0 ? ", " : "", key[i]);
                     }
+                    this->channel->write(R"(], "return_value": %d})",
+                                         return_value);
+                    comma = true;
                 }
                 this->channel->write("]");
                 addComma = true;
@@ -1482,10 +1484,14 @@ bool Debugger::saveState(Module *m, uint8_t *interruptData) {
                 uint8_t overrides_count = *program_state++;
                 for (uint32_t i = 0; i < overrides_count; i++) {
                     uint32_t fidx = read_B32(&program_state);
-                    uint32_t arg = read_B32(&program_state);
+                    uint32_t param_count = m->functions[fidx].type->param_count;
+                    std::vector<uint32_t> key(param_count + 1);
+                    for (uint32_t j = 0; j < param_count; j++) {
+                        key[j] = read_B32(&program_state);
+                    }
+                    key[param_count] = fidx;
                     uint32_t return_value = read_B32(&program_state);
-                    overrides[fidx][arg] = return_value;
-                    debug("Override %d %d %d\n", fidx, arg, return_value);
+                    overrides[key] = return_value;
                 }
                 break;
             }
@@ -1670,7 +1676,7 @@ std::optional<uint32_t> resolve_imported_function(Module *m,
 }
 
 std::string read_string(uint8_t **pos) {
-    std::string str = "";
+    std::string str;
     char c = *(*pos)++;
     while (c != '\0') {
         str += c;
@@ -1680,43 +1686,68 @@ std::string read_string(uint8_t **pos) {
 }
 
 void Debugger::addOverride(Module *m, uint8_t *interruptData) {
-    std::string primitive_name = read_string(&interruptData);
-    uint32_t arg = read_B32(&interruptData);
-    uint32_t result = read_B32(&interruptData);
-
-    std::optional<uint32_t> fidx = resolve_imported_function(m, primitive_name);
+    const std::string primitive_name = read_string(&interruptData);
+    const std::optional<uint32_t> fidx =
+        resolve_imported_function(m, primitive_name);
     if (!fidx) {
         channel->write(
             "Cannot override the result for unknown function \"%s\".\n",
             primitive_name.c_str());
+        channel->write("ack%x;0\n", interruptUnsetOverridePinValue);
         return;
     }
 
-    channel->write("Override %s(%d) = %d.\n", primitive_name.c_str(), arg,
-                   result);
-    overrides[fidx.value()][arg] = result;
+    const uint32_t param_count = m->functions[fidx.value()].type->param_count;
+    std::vector<uint32_t> key(param_count + 1);
+    for (uint32_t i = 0; i < param_count; i++) {
+        key[i] = read_B32(&interruptData);
+    }
+    key[param_count] = fidx.value();
+
+    const uint32_t result = read_B32(&interruptData);
+    channel->write("ack%x;1\n", interruptSetOverridePinValue);
+    overrides[key] = result;
 }
 
 void Debugger::removeOverride(Module *m, uint8_t *interruptData) {
-    std::string primitive_name = read_string(&interruptData);
-    uint32_t arg = read_B32(&interruptData);
-
-    std::optional<uint32_t> fidx = resolve_imported_function(m, primitive_name);
+    const std::string primitive_name = read_string(&interruptData);
+    const std::optional<uint32_t> fidx =
+        resolve_imported_function(m, primitive_name);
     if (!fidx) {
         channel->write("Cannot remove override for unknown function \"%s\".\n",
                        primitive_name.c_str());
+        channel->write("ack%x;0\n", interruptUnsetOverridePinValue);
         return;
     }
 
-    if (overrides[fidx.value()].count(arg) == 0) {
-        channel->write("Override for %s(%d) not found.\n",
-                       primitive_name.c_str(), arg);
+    const uint32_t param_count = m->functions[fidx.value()].type->param_count;
+    std::vector<uint32_t> key(param_count + 1);
+    for (uint32_t i = 0; i < param_count; i++) {
+        key[i] = read_B32(&interruptData);
+    }
+    key[param_count] = fidx.value();
+
+    if (overrides.erase(key) == 0) {
+        channel->write("ack%x;0\n", interruptUnsetOverridePinValue);
         return;
     }
+    channel->write("ack%x;1\n", interruptUnsetOverridePinValue);
+}
 
-    channel->write("Removing override %s(%d) = %d.\n", primitive_name.c_str(),
-                   arg, overrides[fidx.value()][arg]);
-    overrides[fidx.value()].erase(arg);
+bool Debugger::getMockForArgs(Module *m, uint32_t fidx, uint32_t &result) {
+    const uint32_t param_count = m->functions[fidx].type->param_count;
+    std::vector<uint32_t> key(param_count + 1);
+    const ExecutionContext *ectx = m->warduino->execution_context;
+    for (uint32_t i = 0; i < param_count; i++) {
+        key[i] = ectx->stack[ectx->sp - (param_count - i - 1)].value.uint32;
+    }
+    key[param_count] = fidx;
+    const auto it = overrides.find(key);
+    if (it == overrides.end()) {
+        return false;
+    }
+    result = it->second;
+    return true;
 }
 
 bool Debugger::handleContinueFor(Module *m) {
diff --git a/src/Debug/debugger.h b/src/Debug/debugger.h
index c612ddf8..6a241ab8 100644
--- a/src/Debug/debugger.h
+++ b/src/Debug/debugger.h
@@ -110,6 +110,26 @@ enum class SnapshotPolicy : int {
                          // points where primitives are used.
 };
 
+/*
+ * FNV-1a 32bit:
+ * https://datatracker.ietf.org/doc/html/draft-eastlake-fnv-17.html
+ */
+struct FNV1aVectorHash {
+    size_t operator()(const std::vector<uint32_t> &values) const {
+        constexpr uint32_t FNV_offset_basis = 0x811c9dc5;
+        uint32_t result_hash = FNV_offset_basis;
+        for (const uint32_t v : values) {
+            for (int i = 0; i < 4; ++i) {
+                constexpr uint32_t FNV_prime = 0x01000193;
+                const uint8_t byte = (v >> (i * 8)) & 0xff;
+                result_hash ^= byte;
+                result_hash *= FNV_prime;
+            }
+        }
+        return result_hash;
+    }
+};
+
 class Debugger {
    private:
     std::deque<uint8_t *> debugMessages = {};
@@ -130,7 +150,7 @@ class Debugger {
     warduino::mutex *supervisor_mutex;
 
     // Mocking
-    std::unordered_map<uint32_t, std::unordered_map<uint32_t, uint32_t>>
+    std::unordered_map<std::vector<uint32_t>, uint32_t, FNV1aVectorHash>
         overrides;
 
     // Checkpointing
@@ -206,6 +226,11 @@ class Debugger {
 
     bool reset(Module *m);
 
+    //// Handle mocking
+
+    void addOverride(Module *m, uint8_t *interruptData);
+    void removeOverride(Module *m, uint8_t *interruptData);
+
     //// Handle out-of-place debugging
 
     void freeState(Module *m, uint8_t *interruptData);
@@ -308,15 +333,7 @@ class Debugger {
     bool handlePushedEvent(char *bytes) const;
 
     // Concolic Multiverse Debugging
-    inline bool isMocked(uint32_t fidx, uint32_t argument) {
-        return overrides.count(fidx) > 0 && overrides[fidx].count(argument) > 0;
-    }
-    inline uint32_t getMockedValue(uint32_t fidx, uint32_t argument) {
-        return overrides[fidx][argument];
-    }
-
-    void addOverride(Module *m, uint8_t *interruptData);
-    void removeOverride(Module *m, uint8_t *interruptData);
+    bool getMockForArgs(Module *m, uint32_t fidx, uint32_t &result);
 
     // Checkpointing
     void checkpoint(Module *m, bool force = false);
diff --git a/src/Interpreter/instructions.cpp b/src/Interpreter/instructions.cpp
index eb05081a..d2df36d2 100644
--- a/src/Interpreter/instructions.cpp
+++ b/src/Interpreter/instructions.cpp
@@ -305,10 +305,12 @@ bool i_instr_call(Module *m) {
 
         // Mocking only works on primitives, no need to check for it otherwise.
         if (ectx->sp >= 0) {
-            uint32_t arg = ectx->stack[ectx->sp].value.uint32;
-            if (m->warduino->debugger->isMocked(fidx, arg)) {
-                ectx->stack[ectx->sp].value.uint32 =
-                    m->warduino->debugger->getMockedValue(fidx, arg);
+            uint32_t mock_result;
+            if (m->warduino->debugger->getMockForArgs(m, fidx, mock_result)) {
+                const uint32_t param_count =
+                    m->functions[fidx].type->param_count;
+                ectx->sp -= static_cast<int>(param_count) - 1;
+                ectx->stack[ectx->sp].value.uint32 = mock_result;
                 return true;
             }
         }