diff --git a/Machines/Acorn/Archimedes/Video.hpp b/Machines/Acorn/Archimedes/Video.hpp
index e0ca639da..e5215ae5d 100644
--- a/Machines/Acorn/Archimedes/Video.hpp
+++ b/Machines/Acorn/Archimedes/Video.hpp
@@ -124,6 +124,7 @@ struct Video {
 			if(vertical_state_.position == vertical_timing_.period) {
 				vertical_state_.position = 0;
 				address_ = frame_start_;
+				if(address_ == buffer_end_) address_ = buffer_start_;
 
 				entered_sync_ = true;
 				interrupt_observer_.update_interrupts();
@@ -281,10 +282,10 @@ struct Video {
 		return interrupt;
 	}
 
-	void set_frame_start(uint32_t address) 	{	frame_start_ = address;		}
-	void set_buffer_start(uint32_t address)	{	buffer_start_ = address;	}
-	void set_buffer_end(uint32_t address)	{	buffer_end_ = address;		}
-	void set_cursor_start(uint32_t address)	{	cursor_start_ = address;	}
+	void set_frame_start(uint32_t address) 	{	frame_start_ = address & 0x7'ffff;	}
+	void set_buffer_start(uint32_t address)	{	buffer_start_ = address & 0x7'ffff;	}
+	void set_buffer_end(uint32_t address)	{	buffer_end_ = address & 0x7'ffff;	}
+	void set_cursor_start(uint32_t address)	{	cursor_start_ = address & 0x7'ffff;	}
 
 	Outputs::CRT::CRT &crt() 				{ return crt_; }
 	const Outputs::CRT::CRT &crt() const	{ return crt_; }