diff --git a/.github/workflows/arbitrator-ci.yml b/.github/workflows/arbitrator-ci.yml
index a315bff9d1e..4b4d7ad9ed7 100644
--- a/.github/workflows/arbitrator-ci.yml
+++ b/.github/workflows/arbitrator-ci.yml
@@ -139,7 +139,7 @@ jobs:
         uses: actions-rs/cargo@v1
         with:
           command: clippy
-          args: --all --manifest-path arbitrator/Cargo.toml
+          args: --all --manifest-path arbitrator/Cargo.toml -- -D warnings
 
       - name: Run rust tests
         uses: actions-rs/cargo@v1
diff --git a/arbitrator/prover/src/lib.rs b/arbitrator/prover/src/lib.rs
index 0d5ba902239..be6f117b5c8 100644
--- a/arbitrator/prover/src/lib.rs
+++ b/arbitrator/prover/src/lib.rs
@@ -1,7 +1,7 @@
 // Copyright 2021-2022, Offchain Labs, Inc.
 // For license information, see https://github.com/nitro/blob/master/LICENSE
 
-#![allow(clippy::missing_safety_doc)] // We have a lot of unsafe ABI
+#![allow(clippy::missing_safety_doc, clippy::too_many_arguments)]
 
 pub mod binary;
 /// cbindgen:ignore
diff --git a/arbitrator/prover/src/machine.rs b/arbitrator/prover/src/machine.rs
index 4ccf122610f..82f529a7417 100644
--- a/arbitrator/prover/src/machine.rs
+++ b/arbitrator/prover/src/machine.rs
@@ -347,7 +347,7 @@ impl Module {
                     )
                 },
                 func_ty.clone(),
-                &types,
+                types,
             )?);
             host_call_hooks.push(None);
         }
@@ -1061,7 +1061,7 @@ impl Machine {
             expected_type.inputs.push(ArbValueType::I32); // argc
             expected_type.inputs.push(ArbValueType::I32); // argv
             ensure!(
-                &main_module.func_types[f as usize] == &expected_type,
+                main_module.func_types[f as usize] == expected_type,
                 "Run function doesn't match expected signature of [argc, argv]",
             );
             // Go's flags library panics if the argument list is empty.
@@ -1345,7 +1345,9 @@ impl Machine {
 
         let module = self.modules.last().expect("no module");
         let export = module.exports.iter().find(|x| x.0 == func);
-        let export = export.expect(&format!("func {} not found", func)).1;
+        let export = export
+            .unwrap_or_else(|| panic!("func {} not found", func))
+            .1;
 
         self.frame_stack.clear();
         self.block_stack.clear();
@@ -1361,7 +1363,7 @@ impl Machine {
     }
 
     pub fn get_final_result(&self) -> Result<Vec<Value>> {
-        if self.frame_stack.len() != 0 {
+        if !self.frame_stack.is_empty() {
             bail!(
                 "machine has not successfully computed a final result {:?}",
                 self.status
@@ -1452,20 +1454,6 @@ impl Machine {
             match inst.opcode {
                 Opcode::Unreachable => error!(),
                 Opcode::Nop => {}
-                Opcode::Block => {
-                    let idx = inst.argument_data as usize;
-                    self.block_stack.push(idx);
-                    debug_assert!(func.code.len() > idx);
-                }
-                Opcode::EndBlock => {
-                    self.block_stack.pop();
-                }
-                Opcode::EndBlockIf => {
-                    let x = self.value_stack.last().unwrap();
-                    if !x.is_i32_zero() {
-                        self.block_stack.pop().unwrap();
-                    }
-                }
                 Opcode::InitFrame => {
                     let caller_module_internals = self.value_stack.pop().unwrap().assume_u32();
                     let caller_module = self.value_stack.pop().unwrap().assume_u32();
@@ -1493,17 +1481,6 @@ impl Machine {
                         Machine::test_next_instruction(func, &self.pc);
                     }
                 }
-                Opcode::Branch => {
-                    self.pc.inst = self.block_stack.pop().unwrap();
-                    Machine::test_next_instruction(func, &self.pc);
-                }
-                Opcode::BranchIf => {
-                    let x = self.value_stack.pop().unwrap();
-                    if !x.is_i32_zero() {
-                        self.pc.inst = self.block_stack.pop().unwrap();
-                        Machine::test_next_instruction(func, &self.pc);
-                    }
-                }
                 Opcode::Return => {
                     let frame = self.frame_stack.pop().unwrap();
                     match frame.return_ref {
@@ -1868,20 +1845,12 @@ impl Machine {
                     }
                     self.value_stack.push(Value::I64(x));
                 }
-                Opcode::PushStackBoundary => {
-                    self.value_stack.push(Value::StackBoundary);
-                }
                 Opcode::MoveFromStackToInternal => {
                     self.internal_stack.push(self.value_stack.pop().unwrap());
                 }
                 Opcode::MoveFromInternalToStack => {
                     self.value_stack.push(self.internal_stack.pop().unwrap());
                 }
-                Opcode::IsStackBoundary => {
-                    let val = self.value_stack.pop().unwrap();
-                    self.value_stack
-                        .push(Value::I32((val == Value::StackBoundary) as u32));
-                }
                 Opcode::Dup => {
                     let val = self.value_stack.last().cloned().unwrap();
                     self.value_stack.push(val);
diff --git a/arbitrator/prover/src/value.rs b/arbitrator/prover/src/value.rs
index 0b79518fbbc..9267a21782c 100644
--- a/arbitrator/prover/src/value.rs
+++ b/arbitrator/prover/src/value.rs
@@ -20,7 +20,6 @@ pub enum ArbValueType {
     RefNull,
     FuncRef,
     InternalRef,
-    StackBoundary,
 }
 
 impl ArbValueType {
@@ -96,7 +95,6 @@ pub enum Value {
     RefNull,
     FuncRef(u32),
     InternalRef(ProgramCounter),
-    StackBoundary,
 }
 
 impl Value {
@@ -109,7 +107,6 @@ impl Value {
             Value::RefNull => ArbValueType::RefNull,
             Value::FuncRef(_) => ArbValueType::FuncRef,
             Value::InternalRef(_) => ArbValueType::InternalRef,
-            Value::StackBoundary => ArbValueType::StackBoundary,
         }
     }
 
@@ -122,7 +119,6 @@ impl Value {
             Value::RefNull => Bytes32::default(),
             Value::FuncRef(x) => x.into(),
             Value::InternalRef(pc) => pc.serialize(),
-            Value::StackBoundary => Bytes32::default(),
         }
     }
 
@@ -186,9 +182,6 @@ impl Value {
             ArbValueType::RefNull | ArbValueType::FuncRef | ArbValueType::InternalRef => {
                 Value::RefNull
             }
-            ArbValueType::StackBoundary => {
-                panic!("Attempted to make default of StackBoundary type")
-            }
         }
     }
 
@@ -232,10 +225,9 @@ impl Value {
             }
             Value::F32(value) => single!("f32", *value),
             Value::F64(value) => single!("f64", *value),
-            Value::RefNull => format!("null"),
+            Value::RefNull => "null".into(),
             Value::FuncRef(func) => format!("func {}", func),
             Value::InternalRef(pc) => format!("inst {} in {}-{}", pc.inst, pc.module, pc.func),
-            Value::StackBoundary => format!("stack boundary"),
         }
     }
 }
diff --git a/arbitrator/prover/src/wavm.rs b/arbitrator/prover/src/wavm.rs
index a4ef905c079..e8f7fa25573 100644
--- a/arbitrator/prover/src/wavm.rs
+++ b/arbitrator/prover/src/wavm.rs
@@ -78,10 +78,6 @@ impl IBinOpType {
 pub enum Opcode {
     Unreachable,
     Nop,
-    Block,
-    // Loop and If are wrapped into Block
-    Branch,
-    BranchIf,
 
     Return,
     Call,
@@ -137,24 +133,16 @@ pub enum Opcode {
     IBinOp(IntegerValType, IBinOpType),
 
     // Custom opcodes not in WASM. Documented more in "Custom opcodes.md".
-    /// Branch is partially split up into these.
-    EndBlock,
-    /// Custom opcode not in wasm.
-    /// Like "EndBlock" but conditional.
-    /// Keeps its condition on the stack.
-    EndBlockIf,
     /// Custom opcode not in wasm.
     InitFrame,
+    /// Unconditional jump to an arbitrary point in code.
+    ArbitraryJump,
     /// Conditional jump to an arbitrary point in code.
     ArbitraryJumpIf,
-    /// Push a Value::StackBoundary to the stack
-    PushStackBoundary,
     /// Pop a value from the value stack and push it to the internal stack
     MoveFromStackToInternal,
     /// Pop a value from the internal stack and push it to the value stack
     MoveFromInternalToStack,
-    /// Pop a value from the value stack, then push an I32 1 if it's a stack boundary, I32 0 otherwise.
-    IsStackBoundary,
     /// Duplicate the top value on the stack
     Dup,
     /// Call a function in a different module
@@ -175,8 +163,6 @@ pub enum Opcode {
     ReadInboxMessage,
     /// Stop exexcuting the machine and move to the finished status
     HaltAndSetFinished,
-    /// Unconditional jump to an arbitrary point in code.
-    ArbitraryJump,
 }
 
 impl Opcode {
@@ -184,9 +170,6 @@ impl Opcode {
         match self {
             Opcode::Unreachable => 0x00,
             Opcode::Nop => 0x01,
-            Opcode::Block => 0x02,
-            Opcode::Branch => 0x0C,
-            Opcode::BranchIf => 0x0D,
             Opcode::Return => 0x0F,
             Opcode::Call => 0x10,
             Opcode::CallIndirect => 0x11,
@@ -275,14 +258,11 @@ impl Opcode {
                 _ => panic!("Unsupported {:?}", self),
             },
             // Internal instructions:
-            Opcode::EndBlock => 0x8000,
-            Opcode::EndBlockIf => 0x8001,
             Opcode::InitFrame => 0x8002,
-            Opcode::ArbitraryJumpIf => 0x8003,
-            Opcode::PushStackBoundary => 0x8004,
+            Opcode::ArbitraryJump => 0x8003,
+            Opcode::ArbitraryJumpIf => 0x8004,
             Opcode::MoveFromStackToInternal => 0x8005,
             Opcode::MoveFromInternalToStack => 0x8006,
-            Opcode::IsStackBoundary => 0x8007,
             Opcode::Dup => 0x8008,
             Opcode::CrossModuleCall => 0x8009,
             Opcode::CallerModuleInternalCall => 0x800A,
@@ -293,7 +273,6 @@ impl Opcode {
             Opcode::ReadPreImage => 0x8020,
             Opcode::ReadInboxMessage => 0x8021,
             Opcode::HaltAndSetFinished => 0x8022,
-            Opcode::ArbitraryJump => 0x8023,
         }
     }
 
diff --git a/contracts/src/osp/OneStepProver0.sol b/contracts/src/osp/OneStepProver0.sol
index 4b50313cdbd..c364b324697 100644
--- a/contracts/src/osp/OneStepProver0.sol
+++ b/contracts/src/osp/OneStepProver0.sol
@@ -51,8 +51,6 @@ contract OneStepProver0 is IOneStepProver {
             ty = ValueType.F32;
         } else if (opcode == Instructions.F64_CONST) {
             ty = ValueType.F64;
-        } else if (opcode == Instructions.PUSH_STACK_BOUNDARY) {
-            ty = ValueType.STACK_BOUNDARY;
         } else {
             revert("CONST_PUSH_INVALID_OPCODE");
         }
@@ -86,39 +84,6 @@ contract OneStepProver0 is IOneStepProver {
         }
     }
 
-    function executeBlock(
-        Machine memory mach,
-        Module memory,
-        Instruction calldata inst,
-        bytes calldata
-    ) internal pure {
-        uint32 targetPc = uint32(inst.argumentData);
-        require(targetPc == inst.argumentData, "BAD_BLOCK_PC");
-        mach.blockStack.push(targetPc);
-    }
-
-    function executeBranch(
-        Machine memory mach,
-        Module memory,
-        Instruction calldata,
-        bytes calldata
-    ) internal pure {
-        mach.functionPc = mach.blockStack.pop();
-    }
-
-    function executeBranchIf(
-        Machine memory mach,
-        Module memory,
-        Instruction calldata,
-        bytes calldata
-    ) internal pure {
-        uint32 cond = mach.valueStack.pop().assumeI32();
-        if (cond != 0) {
-            // Jump to target
-            mach.functionPc = mach.blockStack.pop();
-        }
-    }
-
     function executeReturn(
         Machine memory mach,
         Module memory,
@@ -419,27 +384,6 @@ contract OneStepProver0 is IOneStepProver {
         );
     }
 
-    function executeEndBlock(
-        Machine memory mach,
-        Module memory,
-        Instruction calldata,
-        bytes calldata
-    ) internal pure {
-        mach.blockStack.pop();
-    }
-
-    function executeEndBlockIf(
-        Machine memory mach,
-        Module memory,
-        Instruction calldata,
-        bytes calldata
-    ) internal pure {
-        uint32 cond = mach.valueStack.peek().assumeI32();
-        if (cond != 0) {
-            mach.blockStack.pop();
-        }
-    }
-
     function executeInitFrame(
         Machine memory mach,
         Module memory,
@@ -476,20 +420,6 @@ contract OneStepProver0 is IOneStepProver {
         }
     }
 
-    function executeIsStackBoundary(
-        Machine memory mach,
-        Module memory,
-        Instruction calldata,
-        bytes calldata
-    ) internal pure {
-        Value memory val = mach.valueStack.pop();
-        uint32 newContents = 0;
-        if (val.valueType == ValueType.STACK_BOUNDARY) {
-            newContents = 1;
-        }
-        mach.valueStack.push(ValueLib.newI32(newContents));
-    }
-
     function executeDup(
         Machine memory mach,
         Module memory,
@@ -519,12 +449,6 @@ contract OneStepProver0 is IOneStepProver {
             impl = executeUnreachable;
         } else if (opcode == Instructions.NOP) {
             impl = executeNop;
-        } else if (opcode == Instructions.BLOCK) {
-            impl = executeBlock;
-        } else if (opcode == Instructions.BRANCH) {
-            impl = executeBranch;
-        } else if (opcode == Instructions.BRANCH_IF) {
-            impl = executeBranchIf;
         } else if (opcode == Instructions.RETURN) {
             impl = executeReturn;
         } else if (opcode == Instructions.CALL) {
@@ -535,10 +459,6 @@ contract OneStepProver0 is IOneStepProver {
             impl = executeCallerModuleInternalCall;
         } else if (opcode == Instructions.CALL_INDIRECT) {
             impl = executeCallIndirect;
-        } else if (opcode == Instructions.END_BLOCK) {
-            impl = executeEndBlock;
-        } else if (opcode == Instructions.END_BLOCK_IF) {
-            impl = executeEndBlockIf;
         } else if (opcode == Instructions.ARBITRARY_JUMP) {
             impl = executeArbitraryJump;
         } else if (opcode == Instructions.ARBITRARY_JUMP_IF) {
@@ -557,18 +477,13 @@ contract OneStepProver0 is IOneStepProver {
             impl = executeDrop;
         } else if (opcode == Instructions.SELECT) {
             impl = executeSelect;
-        } else if (
-            (opcode >= Instructions.I32_CONST && opcode <= Instructions.F64_CONST) ||
-            opcode == Instructions.PUSH_STACK_BOUNDARY
-        ) {
+        } else if (opcode >= Instructions.I32_CONST && opcode <= Instructions.F64_CONST) {
             impl = executeConstPush;
         } else if (
             opcode == Instructions.MOVE_FROM_STACK_TO_INTERNAL ||
             opcode == Instructions.MOVE_FROM_INTERNAL_TO_STACK
         ) {
             impl = executeMoveInternal;
-        } else if (opcode == Instructions.IS_STACK_BOUNDARY) {
-            impl = executeIsStackBoundary;
         } else if (opcode == Instructions.DUP) {
             impl = executeDup;
         } else {
diff --git a/contracts/src/state/Instructions.sol b/contracts/src/state/Instructions.sol
index 625da095c69..196899c93ff 100644
--- a/contracts/src/state/Instructions.sol
+++ b/contracts/src/state/Instructions.sol
@@ -12,9 +12,6 @@ struct Instruction {
 library Instructions {
     uint16 internal constant UNREACHABLE = 0x00;
     uint16 internal constant NOP = 0x01;
-    uint16 internal constant BLOCK = 0x02;
-    uint16 internal constant BRANCH = 0x0C;
-    uint16 internal constant BRANCH_IF = 0x0D;
     uint16 internal constant RETURN = 0x0F;
     uint16 internal constant CALL = 0x10;
     uint16 internal constant CALL_INDIRECT = 0x11;
@@ -129,14 +126,11 @@ library Instructions {
     uint16 internal constant I64_EXTEND_16S = 0xC3;
     uint16 internal constant I64_EXTEND_32S = 0xC4;
 
-    uint16 internal constant END_BLOCK = 0x8000;
-    uint16 internal constant END_BLOCK_IF = 0x8001;
     uint16 internal constant INIT_FRAME = 0x8002;
-    uint16 internal constant ARBITRARY_JUMP_IF = 0x8003;
-    uint16 internal constant PUSH_STACK_BOUNDARY = 0x8004;
+    uint16 internal constant ARBITRARY_JUMP = 0x8003;
+    uint16 internal constant ARBITRARY_JUMP_IF = 0x8004;
     uint16 internal constant MOVE_FROM_STACK_TO_INTERNAL = 0x8005;
     uint16 internal constant MOVE_FROM_INTERNAL_TO_STACK = 0x8006;
-    uint16 internal constant IS_STACK_BOUNDARY = 0x8007;
     uint16 internal constant DUP = 0x8008;
     uint16 internal constant CROSS_MODULE_CALL = 0x8009;
     uint16 internal constant CALLER_MODULE_INTERNAL_CALL = 0x800A;
@@ -150,8 +144,6 @@ library Instructions {
     uint16 internal constant READ_INBOX_MESSAGE = 0x8021;
     uint16 internal constant HALT_AND_SET_FINISHED = 0x8022;
 
-    uint16 internal constant ARBITRARY_JUMP = 0x8023;
-
     uint256 internal constant INBOX_INDEX_SEQUENCER = 0;
     uint256 internal constant INBOX_INDEX_DELAYED = 1;
 
diff --git a/contracts/src/state/Value.sol b/contracts/src/state/Value.sol
index 3784eab6699..6e0a837b2b3 100644
--- a/contracts/src/state/Value.sol
+++ b/contracts/src/state/Value.sol
@@ -11,8 +11,7 @@ enum ValueType {
     F64,
     REF_NULL,
     FUNC_REF,
-    INTERNAL_REF,
-    STACK_BOUNDARY
+    INTERNAL_REF
 }
 
 struct Value {
@@ -26,7 +25,7 @@ library ValueLib {
     }
 
     function maxValueType() internal pure returns (ValueType) {
-        return ValueType.STACK_BOUNDARY;
+        return ValueType.INTERNAL_REF;
     }
 
     function assumeI32(Value memory val) internal pure returns (uint32) {
diff --git a/go.mod b/go.mod
index 00c1117de02..565f907439d 100644
--- a/go.mod
+++ b/go.mod
@@ -106,7 +106,7 @@ require (
 	golang.org/x/crypto v0.0.0-20210322153248-0c34fe9e7dc2
 	golang.org/x/net v0.0.0-20220127200216-cd36cc0744dd // indirect
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c // indirect
-	golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e // indirect
+	golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e
 	golang.org/x/text v0.3.7 // indirect
 	golang.org/x/time v0.0.0-20210220033141-f8bda1e9f3ba // indirect
 	gopkg.in/natefinch/npipe.v2 v2.0.0-20160621034901-c1b8fa8bdcce // indirect