diff --git a/Machines/Acorn/Archimedes/Video.hpp b/Machines/Acorn/Archimedes/Video.hpp
index 0e67087fe..79bc66825 100644
--- a/Machines/Acorn/Archimedes/Video.hpp
+++ b/Machines/Acorn/Archimedes/Video.hpp
@@ -175,6 +175,10 @@ struct Video {
 				pixels_[0] = colours_[next & 0xf];
 				pixels_[1] = colours_[next >> 4];
 				pixels_ += 2;
+			} else {
+				// TODO: don't assume 4bpp here either.
+				++address_;
+				if(address_ == buffer_end_) address_ = buffer_start_;
 			}
 		}