diff --git a/Storage/Disk/DiskImage/Formats/AppleDSK.cpp b/Storage/Disk/DiskImage/Formats/AppleDSK.cpp
index a3c86c2e7..afc0d06c9 100644
--- a/Storage/Disk/DiskImage/Formats/AppleDSK.cpp
+++ b/Storage/Disk/DiskImage/Formats/AppleDSK.cpp
@@ -53,12 +53,12 @@ std::shared_ptr<Track> AppleDSK::get_track_at_position(Track::Address address) {
 	// In either case below, the code aims for exactly 50,000 bits per track.
 	if(sectors_per_track_ == 16) {
 		// Write the sectors.
-		uint8_t sector_number_ = 0;
-		for(std::size_t c = 0; c < 16; ++c) {
+		std::size_t sector_number_ = 0;
+		for(uint8_t c = 0; c < 16; ++c) {
 			segment += Encodings::AppleGCR::six_and_two_sync(10);
-			segment += Encodings::AppleGCR::header(0, track, sector_number_);
+			segment += Encodings::AppleGCR::header(0, track, c);
 			segment += Encodings::AppleGCR::six_and_two_sync(10);
-			segment += Encodings::AppleGCR::six_and_two_data(&track_data[c * 256]);
+			segment += Encodings::AppleGCR::six_and_two_data(&track_data[sector_number_ * 256]);
 
 			// DOS and Pro DOS interleave sectors on disk, and they're represented in a disk
 			// image in physical order rather than logical. So that skew needs to be applied here.
diff --git a/Storage/Disk/Drive.cpp b/Storage/Disk/Drive.cpp
index 5ef0dac5f..f1de0609c 100644
--- a/Storage/Disk/Drive.cpp
+++ b/Storage/Disk/Drive.cpp
@@ -205,9 +205,14 @@ void Drive::setup_track() {
 	assert(track_time_now >= Time(0) && current_event_.length <= Time(1));
 
 	Time time_found = track_->seek_to(track_time_now);
-	assert(time_found >= Time(0) && time_found < Time(1) && time_found <= track_time_now);
 
-	offset = track_time_now - time_found;
+	// time_found can be greater than track_time_now if limited precision caused rounding
+	if(time_found <= track_time_now) {
+		offset = track_time_now - time_found;
+	} else {
+		offset.set_zero();
+	}
+
 	get_next_event(offset);
 }
 
diff --git a/Storage/Disk/Encodings/AppleGCR.cpp b/Storage/Disk/Encodings/AppleGCR.cpp
index 3843859c1..5702d9239 100644
--- a/Storage/Disk/Encodings/AppleGCR.cpp
+++ b/Storage/Disk/Encodings/AppleGCR.cpp
@@ -156,13 +156,26 @@ Storage::Disk::PCMSegment AppleGCR::six_and_two_data(const uint8_t *source) {
 	// six bits.
 	const uint8_t bit_shuffle[] = {0, 2, 1, 3};
 	for(std::size_t c = 0; c < 84; ++c) {
-		segment.data[3 + c] = bit_shuffle[source[c]&3];
-		if(c + 86 < 256) segment.data[3 + c] |= bit_shuffle[source[c + 86]&3] << 2;
-		if(c + 172 < 256) segment.data[3 + c] |= bit_shuffle[source[c + 172]&3] << 4;
+		segment.data[3 + c] =
+			static_cast<uint8_t>(
+				bit_shuffle[source[c]&3] |
+				(bit_shuffle[source[c + 86]&3] << 2) |
+				(bit_shuffle[source[c + 172]&3] << 4)
+			);
 	}
+	segment.data[87] =
+			static_cast<uint8_t>(
+				(bit_shuffle[source[84]&3] << 0) |
+				(bit_shuffle[source[170]&3] << 2)
+			);
+	segment.data[88] =
+			static_cast<uint8_t>(
+				(bit_shuffle[source[85]&3] << 0) |
+				(bit_shuffle[source[171]&3] << 2)
+			);
 
 	for(std::size_t c = 0; c < 256; ++c) {
-		segment.data[3 + 85 + 1 + c] = source[c] >> 2;
+		segment.data[3 + 86 + c] = source[c] >> 2;
 	}
 
 	// Exclusive OR each byte with the one before it.