diff --git a/src/app/rom.h b/src/app/rom.h
index 3a3aad63..2f903eb2 100644
--- a/src/app/rom.h
+++ b/src/app/rom.h
@@ -206,8 +206,16 @@ class Rom : public core::ExperimentFlags {
    */
   absl::Status SaveAllPalettes();
 
+  absl::Status ReadWritePreconditions() {
+    if (!is_loaded_) {
+      return absl::FailedPreconditionError("ROM not loaded");
+    }
+    return absl::OkStatus();
+  }
+
   // Read functions
   absl::StatusOr<uint8_t> ReadByte(int offset) {
+    RETURN_IF_ERROR(ReadWritePreconditions());
     if (offset >= rom_data_.size()) {
       return absl::FailedPreconditionError("Offset out of range");
     }
@@ -215,6 +223,7 @@ class Rom : public core::ExperimentFlags {
   }
 
   absl::StatusOr<uint16_t> ReadWord(int offset) {
+    RETURN_IF_ERROR(ReadWritePreconditions());
     if (offset + 1 >= rom_data_.size()) {
       return absl::FailedPreconditionError("Offset out of range");
     }
@@ -227,8 +236,9 @@ class Rom : public core::ExperimentFlags {
   }
 
   absl::StatusOr<uint32_t> ReadLong(int offset) {
+    RETURN_IF_ERROR(ReadWritePreconditions());
     if (offset + 2 >= rom_data_.size()) {
-      return absl::FailedPreconditionError("Offset out of range");
+      return absl::OutOfRangeError("Offset out of range");
     }
     auto result = (uint32_t)(rom_data_[offset] | (rom_data_[offset + 1] << 8) |
                              (rom_data_[offset + 2] << 16));
@@ -237,8 +247,9 @@ class Rom : public core::ExperimentFlags {
 
   absl::StatusOr<std::vector<uint8_t>> ReadByteVector(uint32_t offset,
                                                       uint32_t length) {
+    RETURN_IF_ERROR(ReadWritePreconditions());
     if (offset + length > rom_data_.size()) {
-      return absl::FailedPreconditionError("Offset and length out of range");
+      return absl::OutOfRangeError("Offset and length out of range");
     }
     std::vector<uint8_t> result;
     for (int i = offset; i < offset + length; i++) {