diff --git a/src/components/ProgramLoader/BinaryFileUpload.tsx b/src/components/ProgramLoader/BinaryFileUpload.tsx
index 648f7ef..bc3dab5 100644
--- a/src/components/ProgramLoader/BinaryFileUpload.tsx
+++ b/src/components/ProgramLoader/BinaryFileUpload.tsx
@@ -49,7 +49,7 @@ export const BinaryFileUpload = ({
         className="my-6 mr-3"
         id="test-file"
         type="file"
-        accept="application/octet-stream"
+        accept=".bin,.pvm"
         onClick={(e) => e.stopPropagation()}
         onChange={(e) => {
           if (e.target.files?.length) {
diff --git a/src/components/ProgramLoader/Loader.tsx b/src/components/ProgramLoader/Loader.tsx
index 5936f58..6c5ca05 100644
--- a/src/components/ProgramLoader/Loader.tsx
+++ b/src/components/ProgramLoader/Loader.tsx
@@ -56,9 +56,7 @@ export const Loader = ({
         <TabsList>
           <TabsTrigger value="upload">JSON tests</TabsTrigger>
           <TabsTrigger value="examples">Examples</TabsTrigger>
-          <TabsTrigger className="hidden lg:inline-flex" value="bytecode">
-            RAW bytecode
-          </TabsTrigger>
+          <TabsTrigger value="bytecode">RAW bytecode</TabsTrigger>
           <TabsTrigger value="assembly">Assembly</TabsTrigger>
         </TabsList>
         <div className="border-2 rounded p-4 flex-1 flex flex-col w-full h-full overflow-auto md:px-5">
diff --git a/src/packages/pvm/pvm/disassemblify.ts b/src/packages/pvm/pvm/disassemblify.ts
index cb51b11..17896b4 100644
--- a/src/packages/pvm/pvm/disassemblify.ts
+++ b/src/packages/pvm/pvm/disassemblify.ts
@@ -5,6 +5,7 @@ import {
   ArgsDecoder,
   instructionArgumentTypeMap,
   createResults,
+  ArgumentType,
 } from "@typeberry/pvm-debugger-adapter";
 import { Instruction } from "./instruction";
 
@@ -20,7 +21,10 @@ export function disassemblify(rawProgram: Uint8Array) {
 
   while (i < code.length) {
     const currentInstruction = code[i];
-    const argumentType = instructionArgumentTypeMap[currentInstruction];
+    const isValidInstruction = Instruction[currentInstruction] !== undefined;
+    const argumentType = isValidInstruction
+      ? instructionArgumentTypeMap[currentInstruction]
+      : ArgumentType.NO_ARGUMENTS;
     const args = createResults()[argumentType];
 
     try {
@@ -41,7 +45,7 @@ export function disassemblify(rawProgram: Uint8Array) {
     const currentInstructionDebug = {
       instructionCode: currentInstruction,
       ...byteToOpCodeMap[currentInstruction],
-      name: Instruction[currentInstruction],
+      name: isValidInstruction ? Instruction[currentInstruction] : `INVALID(${currentInstruction})`,
       instructionBytes: code.slice(i - (args.noOfBytesToSkip ?? 0), i),
       address,
       args,