diff --git a/Machines/Thomson/MO5/MO5.cpp b/Machines/Thomson/MO5/MO5.cpp
index e53b9282c..0cf67ab93 100644
--- a/Machines/Thomson/MO5/MO5.cpp
+++ b/Machines/Thomson/MO5/MO5.cpp
@@ -64,13 +64,13 @@ struct ConcreteMachine:
 		speaker_.set_input_rate(ClockRate);
 		construct_joysticks();
 
-		const auto request = ROM::Request(ROM::Name::ThomasonMO5v11);
+		const auto request = ROM::Request(ROM::Name::ThomsonMO5v11);
 		auto roms = rom_fetcher(request);
 		if(!request.validate(roms)) {
 			throw ROMMachine::Error::MissingROMs;
 		}
 
-		const auto &rom = roms.find(ROM::Name::ThomasonMO5v11)->second;
+		const auto &rom = roms.find(ROM::Name::ThomsonMO5v11)->second;
 		std::copy_n(rom.begin(), rom.size(), rom_.begin());
 
 		Memory::Fuzz(ram_);
diff --git a/Machines/Utility/ROMCatalogue.cpp b/Machines/Utility/ROMCatalogue.cpp
index 251ff5912..81236b015 100644
--- a/Machines/Utility/ROMCatalogue.cpp
+++ b/Machines/Utility/ROMCatalogue.cpp
@@ -1021,7 +1021,7 @@ const std::vector<Description> &Description::all_roms() {
 	// Thomson MO and TO machines.
 	//
 		{
-			ThomasonMO5v1,
+			ThomsonMO5v1,
 			"Thomson",
 			"the Thomson MO5 ROM, version 1",
 			"mo5-v1.0.rom",
@@ -1029,7 +1029,7 @@ const std::vector<Description> &Description::all_roms() {
 			0xf62d2f3au
 		},
 		{
-			ThomasonMO5v11,
+			ThomsonMO5v11,
 			"Thomson",
 			"the Thomson MO5 ROM, version 1.1",
 			"mo5-v1.1.rom",
@@ -1037,6 +1037,15 @@ const std::vector<Description> &Description::all_roms() {
 			0x237c60bfu
 		},
 
+		{
+			ThomsonCD90_640,
+			"Thomson",
+			"the Thomson CD90-640 ROM",
+			"cd90-640.rom",
+			0x7c0,
+			0x5114c0a5u
+		},
+
 	//
 	// Vic-20.
 	//
diff --git a/Machines/Utility/ROMCatalogue.hpp b/Machines/Utility/ROMCatalogue.hpp
index bcb9a6fb8..72b19229e 100644
--- a/Machines/Utility/ROMCatalogue.hpp
+++ b/Machines/Utility/ROMCatalogue.hpp
@@ -176,8 +176,10 @@ enum Name {
 	SinclairQLJS,
 
 	// Thomson MO and TO machines.
-	ThomasonMO5v1,
-	ThomasonMO5v11,
+	ThomsonMO5v1,
+	ThomsonMO5v11,
+
+	ThomsonCD90_640,
 
 	// Vic-20.
 	Vic20BASIC,
diff --git a/ROMImages/Thomson/readme.txt b/ROMImages/Thomson/readme.txt
index a713f4db2..47494f48c 100644
--- a/ROMImages/Thomson/readme.txt
+++ b/ROMImages/Thomson/readme.txt
@@ -3,4 +3,5 @@ ROM files would ordinarily go here; the copyright status of these is uncertain s
 Expected files:
 
 mo5-v1.0.rom — the MO5 ROM, version 1;
-mo5-v1.1.rom — the MO5 ROM, version 1.1.
+mo5-v1.1.rom — the MO5 ROM, version 1.1;
+cd90-640.rom — the CD90-640 floppy disk drive ROM.