diff --git a/Components/1770/1770.cpp b/Components/1770/1770.cpp
index c0e2a1bca..72956a8b9 100644
--- a/Components/1770/1770.cpp
+++ b/Components/1770/1770.cpp
@@ -624,6 +624,18 @@ void WD1770::posit_event(Event new_event_type)
 		{
 			write_byte(0);
 		}
+		WAIT_FOR_EVENT(Event::DataWritten);
+
+		if(is_double_density_)
+		{
+			write_raw_short(Storage::Encodings::MFM::MFMAddressMark);
+			write_byte(command_&1 ? Storage::Encodings::MFM::MFMDataAddressByte : Storage::Encodings::MFM::MFMDeletedDataAddressByte);
+		}
+		else
+		{
+			write_raw_short(command_&1 ? Storage::Encodings::MFM::FMDeletedDataAddressMark : Storage::Encodings::MFM::FMDataAddressMark);
+		}
+
 		WAIT_FOR_EVENT(Event::DataWritten);
 		distance_into_section_ = 0;
 
@@ -716,3 +728,11 @@ void WD1770::write_byte(uint8_t byte)
 {
 	for(int c = 0; c < 8; c++) write_bit((byte << c)&0x80);
 }
+
+void WD1770::write_raw_short(uint16_t value)
+{
+	for(int c = 0; c < 16; c++)
+	{
+		Controller::write_bit(!!((value << c)&0x8000));
+	}
+}
diff --git a/Components/1770/1770.hpp b/Components/1770/1770.hpp
index 3aaefef88..a91796828 100644
--- a/Components/1770/1770.hpp
+++ b/Components/1770/1770.hpp
@@ -124,6 +124,7 @@ class WD1770: public Storage::Disk::Controller {
 		int last_bit_;
 		void write_bit(int bit);
 		void write_byte(uint8_t byte);
+		void write_raw_short(uint16_t value);
 
 		// ID buffer
 		uint8_t header_[6];