diff --git a/hardware/memory/cartridge/ace/ace.go b/hardware/memory/cartridge/ace/ace.go
index 17e95dd8..0684fca5 100644
--- a/hardware/memory/cartridge/ace/ace.go
+++ b/hardware/memory/cartridge/ace/ace.go
@@ -143,11 +143,6 @@ func (cart *Ace) GetBank(_ uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: 0, IsRAM: false}
 }
 
-// Patch implements the mapper.CartMapper interface.
-func (cart *Ace) Patch(_ int, _ uint8) error {
-	return fmt.Errorf("ACE: patching unsupported")
-}
-
 func (cart *Ace) runARM() bool {
 	// call arm once and then check for yield conditions
 	var cycles float32
diff --git a/hardware/memory/cartridge/cartridge.go b/hardware/memory/cartridge/cartridge.go
index d45d0b12..7c21464f 100644
--- a/hardware/memory/cartridge/cartridge.go
+++ b/hardware/memory/cartridge/cartridge.go
@@ -149,12 +149,6 @@ func (cart *Cartridge) Poke(addr uint16, data uint8) error {
 	return cart.mapper.AccessVolatile(addr&memorymap.CartridgeBits, data, true)
 }
 
-// Patch writes to cartridge memory. Offset is measured from the start of
-// cartridge memory. It differs from Poke in that respect.
-func (cart *Cartridge) Patch(offset int, data uint8) error {
-	return cart.mapper.Patch(offset, data)
-}
-
 // Read is an implementation of memory.CPUBus.
 func (cart *Cartridge) Read(addr uint16) (uint8, uint8, error) {
 	return cart.mapper.Access(addr&memorymap.CartridgeBits, false)
@@ -552,10 +546,18 @@ func (cart *Cartridge) CoProcExecutionState() coprocessor.CoProcExecutionState {
 	return coprocessor.CoProcExecutionState{}
 }
 
-// BusStuff implements the mapper.CartBusStuff interface.
+// BusStuff implements the mapper.CartBusStuff interface
 func (cart *Cartridge) BusStuff() (uint8, bool) {
 	if cart.hasBusStuff {
 		return cart.busStuff.BusStuff()
 	}
 	return 0, false
 }
+
+// Patch implements the mapper.CartPatchable interface
+func (cart *Cartridge) Patch(offset int, data uint8) error {
+	if cart, ok := cart.mapper.(mapper.CartPatchable); ok {
+		return cart.Patch(offset, data)
+	}
+	return fmt.Errorf("cartridge is not patchable")
+}
diff --git a/hardware/memory/cartridge/cdf/cdf.go b/hardware/memory/cartridge/cdf/cdf.go
index 4f580ca5..04bb5eb1 100644
--- a/hardware/memory/cartridge/cdf/cdf.go
+++ b/hardware/memory/cartridge/cdf/cdf.go
@@ -424,11 +424,6 @@ func (cart *cdf) GetBank(addr uint16) mapper.BankInfo {
 	}
 }
 
-// Patch implements the mapper.CartMapper interface.
-func (cart *cdf) Patch(offset int, data uint8) error {
-	return fmt.Errorf("CDF: patching unsupported")
-}
-
 // AccessPassive implements the mapper.CartMapper interface.
 func (cart *cdf) AccessPassive(addr uint16, data uint8) error {
 	return nil
diff --git a/hardware/memory/cartridge/dpcplus/dpcplus.go b/hardware/memory/cartridge/dpcplus/dpcplus.go
index 15268c54..3e39bebb 100644
--- a/hardware/memory/cartridge/dpcplus/dpcplus.go
+++ b/hardware/memory/cartridge/dpcplus/dpcplus.go
@@ -682,11 +682,6 @@ func (cart *dpcPlus) GetBank(addr uint16) mapper.BankInfo {
 	}
 }
 
-// Patch implements the mapper.CartMapper interface.
-func (cart *dpcPlus) Patch(offset int, data uint8) error {
-	return fmt.Errorf("DPC+: patching unsupported")
-}
-
 // AccessPassive implements the mapper.CartMapper interface.
 func (cart *dpcPlus) AccessPassive(addr uint16, data uint8) error {
 	return nil
diff --git a/hardware/memory/cartridge/elf/elf.go b/hardware/memory/cartridge/elf/elf.go
index 6c48503f..f5306e40 100644
--- a/hardware/memory/cartridge/elf/elf.go
+++ b/hardware/memory/cartridge/elf/elf.go
@@ -275,11 +275,6 @@ func (cart *Elf) GetBank(_ uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: 0, IsRAM: false}
 }
 
-// Patch implements the mapper.CartMapper interface.
-func (cart *Elf) Patch(_ int, _ uint8) error {
-	return fmt.Errorf("ELF: patching unsupported")
-}
-
 func (cart *Elf) runARM(addr uint16) bool {
 	if cart.mem.stream.active {
 		// do nothing with the ARM if the byte stream is draining
diff --git a/hardware/memory/cartridge/mapper/mapper.go b/hardware/memory/cartridge/mapper/mapper.go
index f9c1866b..08665739 100644
--- a/hardware/memory/cartridge/mapper/mapper.go
+++ b/hardware/memory/cartridge/mapper/mapper.go
@@ -83,12 +83,6 @@ type CartMapper interface {
 	// at the rate specified.
 	Step(clock float32)
 
-	// patch differs from write/poke in that it alters the data as though it
-	// was being read from disk. that is, the offset is measured from the start
-	// of the file. the cartmapper must translate the offset and update the
-	// correct data structure as appropriate.
-	Patch(offset int, data uint8) error
-
 	// return copies of all banks in the cartridge. the disassembly process
 	// uses this to access cartridge data freely and without affecting the
 	// state of the cartridge.
@@ -351,3 +345,13 @@ type CartROMDump interface {
 type CartBusStuff interface {
 	BusStuff() (uint8, bool)
 }
+
+// CartPatchable is implemented by cartridge mappers than can have their binary
+// patched as part of the load process
+type CartPatchable interface {
+	// patch is different to poke in that it alters the data as though it was
+	// being read from disk. that is, the offset is measured from the start of
+	// the file. the cartmapper must translate the offset and update the correct
+	// data structure as appropriate.
+	Patch(offset int, data uint8) error
+}
diff --git a/hardware/memory/cartridge/mapper_3e.go b/hardware/memory/cartridge/mapper_3e.go
index ec74672b..a69fb586 100644
--- a/hardware/memory/cartridge/mapper_3e.go
+++ b/hardware/memory/cartridge/mapper_3e.go
@@ -169,7 +169,7 @@ func (cart *m3e) GetBank(addr uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: cart.state.segment[1], IsRAM: cart.state.segmentIsRAM[1], IsSegmented: true, Segment: 1}
 }
 
-// Patch implements the mapper.CartMapper interface.
+// Patch implements the mapper.CartPatchable interface
 func (cart *m3e) Patch(offset int, data uint8) error {
 	if offset >= cart.bankSize*len(cart.banks) {
 		return fmt.Errorf("3E: patch offset too high (%d)", offset)
diff --git a/hardware/memory/cartridge/mapper_3eplus.go b/hardware/memory/cartridge/mapper_3eplus.go
index 164d3167..45e1b641 100644
--- a/hardware/memory/cartridge/mapper_3eplus.go
+++ b/hardware/memory/cartridge/mapper_3eplus.go
@@ -211,7 +211,7 @@ func (cart *m3ePlus) GetBank(addr uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: cart.state.segment[seg], IsSegmented: true, Segment: seg}
 }
 
-// Patch implements the mapper.CartMapper interface.
+// Patch implements the mapper.CartPatchable interface
 func (cart *m3ePlus) Patch(offset int, data uint8) error {
 	if offset >= cart.bankSize*len(cart.banks) {
 		return fmt.Errorf("3E+: patch offset too high (%d)", offset)
diff --git a/hardware/memory/cartridge/mapper_atari.go b/hardware/memory/cartridge/mapper_atari.go
index d5e59291..ed0aed75 100644
--- a/hardware/memory/cartridge/mapper_atari.go
+++ b/hardware/memory/cartridge/mapper_atari.go
@@ -113,19 +113,19 @@ func hasEmptyArea(d []uint8) bool {
 func (cart *atari) ROMDump(filename string) error {
 	f, err := os.Create(filename)
 	if err != nil {
-		return fmt.Errorf("atari: %w", err)
+		return fmt.Errorf("%s: %w", cart.mappingID, err)
 	}
 	defer func() {
 		err := f.Close()
 		if err != nil {
-			logger.Logf("atari", err.Error())
+			logger.Logf("%s", cart.mappingID, err.Error())
 		}
 	}()
 
 	for _, b := range cart.banks {
 		_, err := f.Write(b)
 		if err != nil {
-			return fmt.Errorf("atari: %w", err)
+			return fmt.Errorf("%s: %w", cart.mappingID, err)
 		}
 	}
 
@@ -212,10 +212,10 @@ func (cart *atari) accessVolatile(addr uint16, data uint8, poke bool) error {
 	return nil
 }
 
-// Patch implements the mapper.CartMapper interface.
+// Patch implements the mapper.CartPatchable interface
 func (cart *atari) Patch(offset int, data uint8) error {
 	if offset >= cart.bankSize*len(cart.banks) {
-		return fmt.Errorf("atari: patch offset too high (%d)", offset)
+		return fmt.Errorf("%s: patch offset too high (%d)", cart.mappingID, offset)
 	}
 
 	bank := offset / cart.bankSize
diff --git a/hardware/memory/cartridge/mapper_cbs.go b/hardware/memory/cartridge/mapper_cbs.go
index 45e8579d..c4ffd356 100644
--- a/hardware/memory/cartridge/mapper_cbs.go
+++ b/hardware/memory/cartridge/mapper_cbs.go
@@ -191,7 +191,7 @@ func (cart *cbs) GetBank(addr uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: cart.state.bank, IsRAM: addr <= 0x00ff}
 }
 
-// Patch implements the mapper.CartMapper interface.
+// Patch implements the mapper.CartPatchable interface
 func (cart *cbs) Patch(offset int, data uint8) error {
 	if offset >= cart.bankSize*len(cart.banks) {
 		return fmt.Errorf("FA: patch offset too high (%d)", offset)
diff --git a/hardware/memory/cartridge/mapper_commavid.go b/hardware/memory/cartridge/mapper_commavid.go
index 1670b759..d1265d23 100644
--- a/hardware/memory/cartridge/mapper_commavid.go
+++ b/hardware/memory/cartridge/mapper_commavid.go
@@ -147,7 +147,7 @@ func (cart *commavid) GetBank(addr uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: 0, IsRAM: addr <= 0x07ff}
 }
 
-// Patch implements the mapper.CartMapper interface.
+// Patch implements the mapper.CartPatchable interface
 func (cart *commavid) Patch(offset int, data uint8) error {
 	if offset >= cart.bankSize {
 		return fmt.Errorf("CV: patch offset too high (%d)", offset)
diff --git a/hardware/memory/cartridge/mapper_df.go b/hardware/memory/cartridge/mapper_df.go
index fd2c07a9..b6fb6960 100644
--- a/hardware/memory/cartridge/mapper_df.go
+++ b/hardware/memory/cartridge/mapper_df.go
@@ -219,7 +219,7 @@ func (cart *df) GetBank(addr uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: cart.state.bank, IsRAM: addr <= 0x00ff}
 }
 
-// Patch implements the mapper.CartMapper interface.
+// Patch implements the mapper.CartPatchable interface
 func (cart *df) Patch(offset int, data uint8) error {
 	if offset >= cart.bankSize*len(cart.banks) {
 		return fmt.Errorf("DF: patch offset too high (%d)", offset)
diff --git a/hardware/memory/cartridge/mapper_dpc.go b/hardware/memory/cartridge/mapper_dpc.go
index 682882eb..54d17574 100644
--- a/hardware/memory/cartridge/mapper_dpc.go
+++ b/hardware/memory/cartridge/mapper_dpc.go
@@ -296,7 +296,7 @@ func (cart *dpc) GetBank(addr uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: cart.state.bank, IsRAM: false}
 }
 
-// Patch implements the mapper.CartMapper interface.
+// Patch implements the mapper.CartPatchable interface
 func (cart *dpc) Patch(offset int, data uint8) error {
 	if offset >= cart.bankSize*len(cart.banks)+len(cart.static.data) {
 		return fmt.Errorf("DPC: patch offset too high (%d)", offset)
diff --git a/hardware/memory/cartridge/mapper_ejected.go b/hardware/memory/cartridge/mapper_ejected.go
index 50ea6387..c196b5ce 100644
--- a/hardware/memory/cartridge/mapper_ejected.go
+++ b/hardware/memory/cartridge/mapper_ejected.go
@@ -72,11 +72,6 @@ func (cart *ejected) GetBank(_ uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: 0, IsRAM: false}
 }
 
-// Patch implements the mapper.CartMapper interface.
-func (cart *ejected) Patch(_ int, _ uint8) error {
-	return Ejected
-}
-
 // AccessPassive implements the mapper.CartMapper interface.
 func (cart *ejected) AccessPassive(_ uint16, _ uint8) error {
 	return nil
diff --git a/hardware/memory/cartridge/mapper_mnetwork.go b/hardware/memory/cartridge/mapper_mnetwork.go
index 21e3ea16..37ef0c9b 100644
--- a/hardware/memory/cartridge/mapper_mnetwork.go
+++ b/hardware/memory/cartridge/mapper_mnetwork.go
@@ -308,7 +308,7 @@ func (cart *mnetwork) GetBank(addr uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: cart.NumBanks() - 1, IsRAM: false, IsSegmented: true, Segment: 1}
 }
 
-// Patch implements the mapper.CartMapper interface.
+// Patch implements the mapper.CartPatchable interface.
 func (cart *mnetwork) Patch(offset int, data uint8) error {
 	if offset >= cart.bankSize*len(cart.banks) {
 		return fmt.Errorf("E7: patch offset too high (%d)", offset)
diff --git a/hardware/memory/cartridge/mapper_parkerbros.go b/hardware/memory/cartridge/mapper_parkerbros.go
index a434ea7c..4ee411e8 100644
--- a/hardware/memory/cartridge/mapper_parkerbros.go
+++ b/hardware/memory/cartridge/mapper_parkerbros.go
@@ -233,7 +233,7 @@ func (cart *parkerBros) GetBank(addr uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: cart.state.segment[seg], IsRAM: false, IsSegmented: true, Segment: seg}
 }
 
-// Patch implements the mapper.CartMapper interface.
+// Patch implements the mapper.CartPatchable interface.
 func (cart *parkerBros) Patch(offset int, data uint8) error {
 	if offset >= cart.bankSize*len(cart.banks) {
 		return fmt.Errorf("E0: patch offset too high (%d)", offset)
diff --git a/hardware/memory/cartridge/mapper_scabs.go b/hardware/memory/cartridge/mapper_scabs.go
index aa813173..4e2b3300 100644
--- a/hardware/memory/cartridge/mapper_scabs.go
+++ b/hardware/memory/cartridge/mapper_scabs.go
@@ -103,11 +103,6 @@ func (cart *scabs) GetBank(_ uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: cart.state.bank, IsRAM: false}
 }
 
-// Patch implements the mapper.CartMapper interface.
-func (cart *scabs) Patch(_ int, _ uint8) error {
-	return nil
-}
-
 // AccessPassive implements the mapper.CartMapper interface.
 func (cart *scabs) AccessPassive(addr uint16, data uint8) error {
 	// "[...] it will be noted that JSR instruction is always followed by an
@@ -181,6 +176,18 @@ func (cart *scabs) CopyBanks() []mapper.BankContent {
 	return c
 }
 
+// Patch implements the mapper.CartPatchable interface
+func (cart *scabs) Patch(offset int, data uint8) error {
+	if offset >= cart.bankSize*len(cart.banks) {
+		return fmt.Errorf("FE: patch offset too high (%d)", offset)
+	}
+
+	bank := offset / cart.bankSize
+	offset %= cart.bankSize
+	cart.banks[bank][offset] = data
+	return nil
+}
+
 type scabsState struct {
 	bank       int
 	bankSwitch int
diff --git a/hardware/memory/cartridge/mapper_superbank.go b/hardware/memory/cartridge/mapper_superbank.go
index 0dadabb5..801111e8 100644
--- a/hardware/memory/cartridge/mapper_superbank.go
+++ b/hardware/memory/cartridge/mapper_superbank.go
@@ -121,7 +121,7 @@ func (cart *superbank) GetBank(addr uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: cart.state.bank, IsRAM: false}
 }
 
-// Patch implements the mapper.CartMapper interface.
+// Patch implements the mapper.CartPatchable interface.
 func (cart *superbank) Patch(offset int, data uint8) error {
 	if offset >= cart.bankSize*len(cart.banks) {
 		return fmt.Errorf("SB: patch offset too high (%d)", offset)
diff --git a/hardware/memory/cartridge/mapper_tigervision.go b/hardware/memory/cartridge/mapper_tigervision.go
index db395993..ef25b8ab 100644
--- a/hardware/memory/cartridge/mapper_tigervision.go
+++ b/hardware/memory/cartridge/mapper_tigervision.go
@@ -148,7 +148,7 @@ func (cart *tigervision) GetBank(addr uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: cart.state.segment[1], IsRAM: false, IsSegmented: true, Segment: 1}
 }
 
-// Patch implements the mapper.CartMapper interface.
+// Patch implements the mapper.CartPatchable interface.
 func (cart *tigervision) Patch(offset int, data uint8) error {
 	if offset >= cart.bankSize*len(cart.banks) {
 		return fmt.Errorf("3F: patch offset too high (%d)", offset)
diff --git a/hardware/memory/cartridge/mapper_ua.go b/hardware/memory/cartridge/mapper_ua.go
index 5ddf5604..7e6e5a39 100644
--- a/hardware/memory/cartridge/mapper_ua.go
+++ b/hardware/memory/cartridge/mapper_ua.go
@@ -121,11 +121,6 @@ func (cart *ua) GetBank(addr uint16) mapper.BankInfo {
 	return mapper.BankInfo{Number: cart.bank}
 }
 
-// Patch implements the mapper.CartMapper interface
-func (cart *ua) Patch(offset int, data uint8) error {
-	return fmt.Errorf("UA: patching unsupported")
-}
-
 // AccessPassive implements the mapper.CartMapper interface
 func (cart *ua) AccessPassive(addr uint16, data uint8) error {
 	switch addr & 0x1260 {
@@ -160,3 +155,15 @@ func (cart *ua) CopyBanks() []mapper.BankContent {
 	}
 	return c
 }
+
+// Patch implements the mapper.CartPatchable interface
+func (cart *ua) Patch(offset int, data uint8) error {
+	if offset >= cart.bankSize*len(cart.banks) {
+		return fmt.Errorf("UA: patch offset too high (%d)", offset)
+	}
+
+	bank := offset / cart.bankSize
+	offset %= cart.bankSize
+	cart.banks[bank][offset] = data
+	return nil
+}
diff --git a/hardware/memory/cartridge/moviecart/moviecart.go b/hardware/memory/cartridge/moviecart/moviecart.go
index 3de9372e..9127f1e8 100644
--- a/hardware/memory/cartridge/moviecart/moviecart.go
+++ b/hardware/memory/cartridge/moviecart/moviecart.go
@@ -374,11 +374,6 @@ func (cart *Moviecart) AccessPassive(addr uint16, data uint8) error {
 func (cart *Moviecart) Step(clock float32) {
 }
 
-// Patch implements the mapper.CartMapper interface.
-func (cart *Moviecart) Patch(offset int, data uint8) error {
-	return nil
-}
-
 // CopyBanks implements the mapper.CartMapper interface.
 func (cart *Moviecart) CopyBanks() []mapper.BankContent {
 	// note that as it is, this will be a copy of the core program without any
diff --git a/hardware/memory/cartridge/plusrom/plusrom.go b/hardware/memory/cartridge/plusrom/plusrom.go
index 154c0b21..a3a88996 100644
--- a/hardware/memory/cartridge/plusrom/plusrom.go
+++ b/hardware/memory/cartridge/plusrom/plusrom.go
@@ -239,11 +239,6 @@ func (cart *PlusROM) GetBank(addr uint16) mapper.BankInfo {
 	return cart.state.child.GetBank(addr)
 }
 
-// Patch implements the mapper.CartMapper interface.
-func (cart *PlusROM) Patch(offset int, data uint8) error {
-	return cart.state.child.Patch(offset, data)
-}
-
 // AccessPassive implements the mapper.CartMapper interface.
 func (cart *PlusROM) AccessPassive(addr uint16, data uint8) error {
 	return cart.state.child.AccessPassive(addr, data)
@@ -262,65 +257,73 @@ func (cart *PlusROM) CopyBanks() []mapper.BankContent {
 
 // GetGetRegisters implements the mapper.CartRegistersBus interface.
 func (cart *PlusROM) GetRegisters() mapper.CartRegisters {
-	if rb, ok := cart.state.child.(mapper.CartRegistersBus); ok {
-		return rb.GetRegisters()
+	if cart, ok := cart.state.child.(mapper.CartRegistersBus); ok {
+		return cart.GetRegisters()
 	}
 	return nil
 }
 
 // PutRegister implements the mapper.CartRegistersBus interface.
 func (cart *PlusROM) PutRegister(register string, data string) {
-	if rb, ok := cart.state.child.(mapper.CartRegistersBus); ok {
-		rb.PutRegister(register, data)
+	if cart, ok := cart.state.child.(mapper.CartRegistersBus); ok {
+		cart.PutRegister(register, data)
 	}
 }
 
 // GetRAM implements the mapper.CartRAMbus interface.
 func (cart *PlusROM) GetRAM() []mapper.CartRAM {
-	if rb, ok := cart.state.child.(mapper.CartRAMbus); ok {
-		return rb.GetRAM()
+	if cart, ok := cart.state.child.(mapper.CartRAMbus); ok {
+		return cart.GetRAM()
 	}
 	return nil
 }
 
 // PutRAM implements the mapper.CartRAMbus interface.
 func (cart *PlusROM) PutRAM(bank int, idx int, data uint8) {
-	if rb, ok := cart.state.child.(mapper.CartRAMbus); ok {
-		rb.PutRAM(bank, idx, data)
+	if cart, ok := cart.state.child.(mapper.CartRAMbus); ok {
+		cart.PutRAM(bank, idx, data)
 	}
 }
 
 // GetStatic implements the mapper.CartStaticBus interface.
 func (cart *PlusROM) GetStatic() mapper.CartStatic {
-	if sb, ok := cart.state.child.(mapper.CartStaticBus); ok {
-		return sb.GetStatic()
+	if cart, ok := cart.state.child.(mapper.CartStaticBus); ok {
+		return cart.GetStatic()
 	}
 	return nil
 }
 
 // PutStatic implements the mapper.CartStaticBus interface.
 func (cart *PlusROM) PutStatic(segment string, idx int, data uint8) bool {
-	if sb, ok := cart.state.child.(mapper.CartStaticBus); ok {
-		return sb.PutStatic(segment, idx, data)
+	if cart, ok := cart.state.child.(mapper.CartStaticBus); ok {
+		return cart.PutStatic(segment, idx, data)
 	}
 	return true
 }
 
 // Rewind implements the mapper.CartTapeBus interface.
 func (cart *PlusROM) Rewind() {
-	if sb, ok := cart.state.child.(mapper.CartTapeBus); ok {
-		sb.Rewind()
+	if cart, ok := cart.state.child.(mapper.CartTapeBus); ok {
+		cart.Rewind()
 	}
 }
 
 // GetTapeState implements the mapper.CartTapeBus interface.
 func (cart *PlusROM) GetTapeState() (bool, mapper.CartTapeState) {
-	if sb, ok := cart.state.child.(mapper.CartTapeBus); ok {
-		return sb.GetTapeState()
+	if cart, ok := cart.state.child.(mapper.CartTapeBus); ok {
+		return cart.GetTapeState()
 	}
 	return false, mapper.CartTapeState{}
 }
 
+// Patch implements the mapper.CartPatchable interface.
+func (cart *PlusROM) Patch(offset int, data uint8) error {
+	if cart, ok := cart.state.child.(mapper.CartPatchable); ok {
+		return cart.Patch(offset, data)
+	}
+	return nil
+}
+
 // RewindBoundary implements the mapper.CartRewindBoundary interface.
 func (cart *PlusROM) RewindBoundary() bool {
 	if cart.rewindBoundary {
diff --git a/hardware/memory/cartridge/supercharger/supercharger.go b/hardware/memory/cartridge/supercharger/supercharger.go
index d617b3b1..74e1cf24 100644
--- a/hardware/memory/cartridge/supercharger/supercharger.go
+++ b/hardware/memory/cartridge/supercharger/supercharger.go
@@ -283,11 +283,6 @@ func (cart *Supercharger) GetBank(addr uint16) mapper.BankInfo {
 	panic("unknown banking method")
 }
 
-// Patch implements the mapper.CartMapper interface.
-func (cart *Supercharger) Patch(_ int, _ uint8) error {
-	return fmt.Errorf("supercharger: not patchable")
-}
-
 // AccessPassive implements the mapper.CartMapper interface.
 func (cart *Supercharger) AccessPassive(addr uint16, _ uint8) error {
 	cart.state.registers.transitionCount(addr)
diff --git a/patch/patch.go b/patch/patch.go
index 9014fdd4..55cc4b56 100644
--- a/patch/patch.go
+++ b/patch/patch.go
@@ -35,7 +35,7 @@ const neoSeparator = ":"
 // CartridgeMemory applies the contents of a patch file to cartridge memory.
 // Currently, patch file must be in the patches sub-directory of the
 // resource path (see paths package).
-func CartridgeMemory(mem *cartridge.Cartridge, patchFile string) (bool, error) {
+func CartridgeMemory(cart *cartridge.Cartridge, patchFile string) (bool, error) {
 	var err error
 
 	p, err := resources.JoinPath(patchPath, patchFile)
@@ -71,7 +71,7 @@ func CartridgeMemory(mem *cartridge.Cartridge, patchFile string) (bool, error) {
 	// if first character is a hyphen then we'll assume this is a "neo" style
 	// patch file
 	if buffer[0] == neoComment {
-		err = neoStyle(mem, buffer)
+		err = neoStyle(cart, buffer)
 		if err != nil {
 			return false, fmt.Errorf("patch: %w", err)
 		}
@@ -79,7 +79,7 @@ func CartridgeMemory(mem *cartridge.Cartridge, patchFile string) (bool, error) {
 	}
 
 	// otherwise assume it is a "cmp" style patch file
-	err = cmpStyle(mem, buffer)
+	err = cmpStyle(cart, buffer)
 	if err != nil {
 		return false, fmt.Errorf("patch: %w", err)
 	}
@@ -87,7 +87,7 @@ func CartridgeMemory(mem *cartridge.Cartridge, patchFile string) (bool, error) {
 }
 
 // cmp -l <old_file> <new_file>.
-func cmpStyle(mem *cartridge.Cartridge, buffer []byte) error {
+func cmpStyle(cart *cartridge.Cartridge, buffer []byte) error {
 	// walk through lines
 	lines := strings.Split(string(buffer), "\n")
 	for i, s := range lines {
@@ -125,13 +125,13 @@ func cmpStyle(mem *cartridge.Cartridge, buffer []byte) error {
 		}
 
 		// check that the patch is correct
-		o, _ := mem.Peek(uint16(offset))
+		o, _ := cart.Peek(uint16(offset))
 		if o != uint8(old) {
 			return fmt.Errorf("cmp: line %d: byte at offset %04x does not match expected byte (%02x instead of %02x)", i, offset, o, old)
 		}
 
 		// patch memory
-		err = mem.Patch(int(offset), uint8(patch))
+		err = cart.Patch(int(offset), uint8(patch))
 		if err != nil {
 			return fmt.Errorf("cmp: %w", err)
 		}
@@ -139,7 +139,7 @@ func cmpStyle(mem *cartridge.Cartridge, buffer []byte) error {
 	return nil
 }
 
-func neoStyle(mem *cartridge.Cartridge, buffer []byte) error {
+func neoStyle(cart *cartridge.Cartridge, buffer []byte) error {
 	// walk through lines
 	lines := strings.Split(string(buffer), "\n")
 	for i, s := range lines {
@@ -188,7 +188,7 @@ func neoStyle(mem *cartridge.Cartridge, buffer []byte) error {
 			}
 
 			// patch memory
-			err = mem.Patch(int(offset), uint8(v))
+			err = cart.Patch(int(offset), uint8(v))
 			if err != nil {
 				return fmt.Errorf("neo: line %d: %w", i, err)
 			}