diff --git a/repos/os/src/drivers/ahci/ahci.h b/repos/os/src/drivers/ahci/ahci.h
index 31b87541a..123367fb5 100644
--- a/repos/os/src/drivers/ahci/ahci.h
+++ b/repos/os/src/drivers/ahci/ahci.h
@@ -250,6 +250,13 @@ namespace Ahci {
 			write<Sector0_7::Tag>(slot);
 		}
 
+		void flush_cache_ext()
+		{
+			write<Bits::C>(1);
+			write<Device::Lba>(0);
+			write<Command>(0xea);
+		}
+
 		void atapi()
 		{
 			write<Bits::C>(1);
diff --git a/repos/os/src/drivers/ahci/ata_protocol.h b/repos/os/src/drivers/ahci/ata_protocol.h
index d3c53ca88..adecb5537 100644
--- a/repos/os/src/drivers/ahci/ata_protocol.h
+++ b/repos/os/src/drivers/ahci/ata_protocol.h
@@ -171,10 +171,14 @@ class Ata::Protocol : public Ahci::Protocol, Noncopyable
 				    (pending_start >= block_number && pending_start <= end) ||
 				    (pending_end   >= block_number && pending_end   <= end)) {
 
-					warning("overlap: "
+					warning("overlap: ",
 					        "pending ", pending_start,
-					        " + ", req.operation.count, ", "
-					        "request: ", block_number, " + ", request.operation.count);
+					        " + ", req.operation.count,
+									" (", req.operation.type == Block::Operation::Type::WRITE ?
+									"write" : "read", "), ",
+					        "request: ", block_number, " + ", request.operation.count,
+									" (", request.operation.type == Block::Operation::Type::WRITE ?
+									"write" : "read", ")");
 					return true;
 				}
 
@@ -248,10 +252,14 @@ class Ata::Protocol : public Ahci::Protocol, Noncopyable
 
 		void handle_irq(Port &port) override
 		{
+			unsigned is = port.read<Port::Is>();
+
 			/* ncg */
-			if (_ncq_support(port))
-				while (Port::Is::Sdbs::get(port.read<Port::Is>()))
+			if (_ncq_support(port) && Port::Is::Fpdma_irq::get(is))
+				do {
 					port.ack_irq();
+				}
+				while (Port::Is::Sdbs::get(port.read<Port::Is>()));
 			/* normal dma */
 			else if (Port::Is::Dma_ext_irq::get(port.read<Port::Is>()))
 				port.ack_irq();
@@ -272,14 +280,16 @@ class Ata::Protocol : public Ahci::Protocol, Noncopyable
 
 		Response submit(Port &port, Block::Request const request) override
 		{
-			if (port.sanity_check(request) == false || port.dma_base == 0)
-				return Response::REJECTED;
-
 			if (_writeable == false && request.operation.type == Block::Operation::Type::WRITE)
 				return Response::REJECTED;
 
-			if (_overlap_check(request))
-				return Response::RETRY;
+			if (Block::Operation::has_payload(request.operation.type)) {
+				if (port.sanity_check(request) == false || port.dma_base == 0)
+					return Response::REJECTED;
+
+				if (_overlap_check(request))
+					return Response::RETRY;
+			}
 
 			Request *r = _slots.get();
 
@@ -298,21 +308,26 @@ class Ata::Protocol : public Ahci::Protocol, Noncopyable
 			                    op.count * _block_size());
 
 			/* setup ATA command */
-			bool read = op.type == Block::Operation::Type::READ;
 
-			if (_ncq_support(port)) {
-				table.fis.fpdma(read, op.block_number, op.count, slot);
+			/* write bit for command header + read/write ATA requests */
+			bool const write = (op.type == Block::Operation::Type::WRITE);
+			bool const sync  = (op.type == Block::Operation::Type::SYNC);
+
+			if (sync) {
+				table.fis.flush_cache_ext();
+			} else if (_ncq_support(port)) {
+				table.fis.fpdma(write == false, op.block_number, op.count, slot);
 				/* ensure that 'Cmd::St' is 1 before writing 'Sact' */
 				port.start();
 				/* set pending */
 				port.write<Port::Sact>(1U << slot);
 			} else {
-				table.fis.dma_ext(read, op.block_number, op.count);
+				table.fis.dma_ext(write == false, op.block_number, op.count);
 			}
 
 			/* set or clear write flag in command header */
 			Command_header header(port.command_header_addr(slot));
-			header.write<Command_header::Bits::W>(read ? 0 : 1);
+			header.write<Command_header::Bits::W>(write ? 1 : 0);
 			header.clear_byte_count();
 
 			port.execute(slot);
diff --git a/repos/os/src/drivers/ahci/atapi_protocol.h b/repos/os/src/drivers/ahci/atapi_protocol.h
index d552cfeb3..d39693e33 100644
--- a/repos/os/src/drivers/ahci/atapi_protocol.h
+++ b/repos/os/src/drivers/ahci/atapi_protocol.h
@@ -148,8 +148,8 @@ class Atapi::Protocol : public Ahci::Protocol, Noncopyable
 
 		Response submit(Port &port, Block::Request const request) override
 		{
-			if (port.sanity_check(request) == false || port.dma_base == 0 ||
-			    request.operation.type != Block::Operation::Type::READ)
+			if (request.operation.type != Block::Operation::Type::READ ||
+			    port.sanity_check(request) == false || port.dma_base == 0)
 				return Response::REJECTED;
 
 			if (_pending.operation.valid())
diff --git a/repos/os/src/drivers/ahci/main.cc b/repos/os/src/drivers/ahci/main.cc
index 9b1192c02..9f184c5c9 100644
--- a/repos/os/src/drivers/ahci/main.cc
+++ b/repos/os/src/drivers/ahci/main.cc
@@ -275,8 +275,9 @@ struct Ahci::Block_session_component : Rpc_object<Block::Session>,
 
 				Response response = Response::RETRY;
 
-				/* only READ/WRITE requests, others are noops for now */
-				if (Block::Operation::has_payload(request.operation.type) == false) {
+				/* ignored operations */
+				if (request.operation.type == Block::Operation::Type::TRIM ||
+				    request.operation.type == Block::Operation::Type::INVALID) {
 					request.success = true;
 					progress = true;
 					return Response::REJECTED;