diff --git a/src/add-ons/kernel/busses/scsi/ahci/ahci_port.cpp b/src/add-ons/kernel/busses/scsi/ahci/ahci_port.cpp
index 753fcd9d3f..ef468734d6 100644
--- a/src/add-ons/kernel/busses/scsi/ahci/ahci_port.cpp
+++ b/src/add-ons/kernel/busses/scsi/ahci/ahci_port.cpp
@@ -43,6 +43,7 @@ AHCIPort::AHCIPort(AHCIController *controller, int index)
 	fSectorSize(0),
 	fSectorCount(0),
 	fIsATAPI(false),
+	fTestUnitReadyActive(false),
 	fResetPort(false),
 	fError(false)
 {
@@ -140,7 +141,6 @@ AHCIPort::Init2()
 	FlushPostedWrites();
 
 	ResetPort(true);
-	PostReset();
 
 	TRACE("ie   0x%08lx\n", fRegs->ie);
 	TRACE("is   0x%08lx\n", fRegs->is);
@@ -233,7 +233,8 @@ AHCIPort::ResetDevice()
 status_t
 AHCIPort::ResetPort(bool forceDeviceReset)
 {
-	TRACE("AHCIPort::ResetPort port %d\n", fIndex);
+	if (!fTestUnitReadyActive)
+		TRACE("AHCIPort::ResetPort port %d\n", fIndex);
 
 	// stop DMA engine
 	fRegs->cmd &= ~PORT_CMD_ST;
@@ -246,8 +247,10 @@ AHCIPort::ResetPort(bool forceDeviceReset)
 
 	bool deviceBusy = fRegs->tfd & (ATA_BSY | ATA_DRQ);
 
-	TRACE("AHCIPort::ResetPort port %d, deviceBusy %d, forceDeviceReset %d\n",
-		  fIndex, deviceBusy, forceDeviceReset);
+	if (!fTestUnitReadyActive) {
+		TRACE("AHCIPort::ResetPort port %d, deviceBusy %d, "
+			"forceDeviceReset %d\n", fIndex, deviceBusy, forceDeviceReset);
+	}
 
 	if (deviceBusy || forceDeviceReset)
 		ResetDevice();
@@ -256,14 +259,15 @@ AHCIPort::ResetPort(bool forceDeviceReset)
 	fRegs->cmd |= PORT_CMD_ST;
 	FlushPostedWrites();
 
-	return B_OK;
+	return PostReset();
 }
 
 
 status_t
 AHCIPort::PostReset()
 {
-	TRACE("AHCIPort::PostReset port %d\n", fIndex);
+	if (!fTestUnitReadyActive)
+		TRACE("AHCIPort::PostReset port %d\n", fIndex);
 
 	if ((fRegs->ssts & 0xf) != 0x3 || (fRegs->tfd & 0xff) == 0x7f) {
 		TRACE("AHCIPort::PostReset port %d: no device\n", fIndex);
@@ -289,9 +293,11 @@ AHCIPort::PostReset()
 		fRegs->cmd &= ~PORT_CMD_ATAPI;
 	FlushPostedWrites();
 
-	TRACE("device signature 0x%08lx (%s)\n", fRegs->sig,
-		(fRegs->sig == 0xeb140101) ? "ATAPI" : (fRegs->sig == 0x00000101) ?
-			"ATA" : "unknown");
+	if (!fTestUnitReadyActive) {
+		TRACE("device signature 0x%08lx (%s)\n", fRegs->sig,
+			(fRegs->sig == 0xeb140101) ? "ATAPI" : (fRegs->sig == 0x00000101) ?
+				"ATA" : "unknown");
+	}
 
 	return B_OK;
 }
@@ -345,20 +351,25 @@ AHCIPort::InterruptErrorHandler(uint32 is)
 {
 	uint32 ci = fRegs->ci;
 
-	TRACE("AHCIPort::InterruptErrorHandler port %d, fCommandsActive 0x%08lx, "
-		"is 0x%08lx, ci 0x%08lx\n", fIndex, fCommandsActive, is, ci);
+	if (!fTestUnitReadyActive) {
+		TRACE("AHCIPort::InterruptErrorHandler port %d, "
+			"fCommandsActive 0x%08lx, is 0x%08lx, ci 0x%08lx\n", fIndex,
+			fCommandsActive, is, ci);
 
-	TRACE("ssts 0x%08lx\n", fRegs->ssts);
-	TRACE("sctl 0x%08lx\n", fRegs->sctl);
-	TRACE("serr 0x%08lx\n", fRegs->serr);
-	TRACE("sact 0x%08lx\n", fRegs->sact);
+		TRACE("ssts 0x%08lx\n", fRegs->ssts);
+		TRACE("sctl 0x%08lx\n", fRegs->sctl);
+		TRACE("serr 0x%08lx\n", fRegs->serr);
+		TRACE("sact 0x%08lx\n", fRegs->sact);
+	}
 
 	// read and clear SError
 	uint32 serr = fRegs->serr;
 	fRegs->serr = serr;
 
 	if (is & PORT_INT_TFE) {
-		TRACE("Task File Error\n");
+		if (!fTestUnitReadyActive)
+			TRACE("Task File Error\n");
+
 		fResetPort = true;
 		fError = true;
 	}
@@ -740,6 +751,7 @@ AHCIPort::ExecuteSataRequest(sata_request *request, bool isWrite)
 	fCommandList->cfl = 5; // 20 bytes, length in DWORDS 
 	memcpy((char *)fCommandTable->cfis, request->fis(), 20);
 
+	fTestUnitReadyActive = request->is_test_unit_ready();
 	if (request->is_atapi()) {
 		// ATAPI PACKET is a 12 or 16 byte SCSI command
 		memset((char *)fCommandTable->acmd, 0, 32);
@@ -755,7 +767,7 @@ AHCIPort::ExecuteSataRequest(sata_request *request, bool isWrite)
 
 	if (wait_until_clear(&fRegs->tfd, ATA_BSY | ATA_DRQ, 1000000) < B_OK) {
 		TRACE("ExecuteAtaRequest port %d: device is busy\n", fIndex);
-		fResetPort = true;
+		ResetPort();
 		FinishTransfer();
 		request->abort();
 		return;
@@ -763,9 +775,9 @@ AHCIPort::ExecuteSataRequest(sata_request *request, bool isWrite)
 
 	cpu_status cpu = disable_interrupts();
 	acquire_spinlock(&fSpinlock);
+	fCommandsActive |= 1;
 	fRegs->ci = 1;
 	FlushPostedWrites();
-	fCommandsActive |= 1;
 	release_spinlock(&fSpinlock);
 	restore_interrupts(cpu);
 
@@ -790,13 +802,17 @@ AHCIPort::ExecuteSataRequest(sata_request *request, bool isWrite)
 	TRACE("tfd  0x%08lx\n", fRegs->tfd);
 */
 
+	if (fResetPort || status == B_TIMED_OUT) {
+		fResetPort = false;
+		ResetPort();
+	}
+
 	size_t bytesTransfered = fCommandList->prdbc;
 
 	FinishTransfer();
 
 	if (status == B_TIMED_OUT) {
 		TRACE("ExecuteAtaRequest port %d: device timeout\n", fIndex);
-		fResetPort = true;
 		request->abort();
 	} else {
 		request->finish(tfd, bytesTransfered);
@@ -807,12 +823,6 @@ AHCIPort::ExecuteSataRequest(sata_request *request, bool isWrite)
 void
 AHCIPort::ScsiExecuteRequest(scsi_ccb *request)
 {
-	if (fResetPort) {
-		fResetPort = false;
-		ResetPort();
-		PostReset();
-	}
-
 //	TRACE("AHCIPort::ScsiExecuteRequest port %d, opcode 0x%02x, length %u\n", fIndex, request->cdb[0], request->cdb_length);
 
 	if (fIsATAPI && request->cdb[0] != SCSI_OP_INQUIRY) {
diff --git a/src/add-ons/kernel/busses/scsi/ahci/ahci_port.h b/src/add-ons/kernel/busses/scsi/ahci/ahci_port.h
index 90eeb8b324..97814584e7 100644
--- a/src/add-ons/kernel/busses/scsi/ahci/ahci_port.h
+++ b/src/add-ons/kernel/busses/scsi/ahci/ahci_port.h
@@ -67,6 +67,7 @@ private:
 	uint32							fSectorSize;
 	uint64							fSectorCount;
 	bool							fIsATAPI;
+	bool							fTestUnitReadyActive;
 	bool							fResetPort;
 	bool							fError;
 
diff --git a/src/add-ons/kernel/busses/scsi/ahci/sata_request.cpp b/src/add-ons/kernel/busses/scsi/ahci/sata_request.cpp
index 1a4bbb0e17..39fb6012a7 100644
--- a/src/add-ons/kernel/busses/scsi/ahci/sata_request.cpp
+++ b/src/add-ons/kernel/busses/scsi/ahci/sata_request.cpp
@@ -105,8 +105,13 @@ sata_request::finish(int tfd, size_t bytesTransfered)
 	if (tfd & (ATA_ERR | ATA_DF)) {
 		uint8 status = tfd & 0xff;
 		uint8 error = (tfd >> 8) & 0xff;
-		dprintf("ahci: sata_request::finish ATA command 0x%02x failed\n", fFis[2]);
-		dprintf("ahci: sata_request::finish status 0x%02x, error 0x%02x\n", status, error);
+
+		if (!is_test_unit_ready()) {
+			dprintf("ahci: sata_request::finish ATA command 0x%02x failed\n",
+				fFis[2]);
+			dprintf("ahci: sata_request::finish status 0x%02x, error 0x%02x\n",
+				status, error);
+		}
 	}
 
 	if (fCcb) {
@@ -116,13 +121,16 @@ sata_request::finish(int tfd, size_t bytesTransfered)
 		if (tfd & (ATA_ERR | ATA_DF)) {
 			fCcb->subsys_status = SCSI_REQ_CMP_ERR;
 			if (fIsATAPI) {
-				dprintf("ahci: sata_request::finish ATAPI packet %02x %02x %02x %02x "
+				if (!is_test_unit_ready()) {
+					dprintf("ahci: sata_request::finish ATAPI packet %02x %02x %02x %02x "
 						"%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x (len %d)\n",
 						fCcb->cdb[0], fCcb->cdb[1], fCcb->cdb[2], fCcb->cdb[3],
 						fCcb->cdb[4], fCcb->cdb[5], fCcb->cdb[6], fCcb->cdb[7],
 						fCcb->cdb[8], fCcb->cdb[9], fCcb->cdb[10], fCcb->cdb[11],
 						fCcb->cdb[12], fCcb->cdb[13], fCcb->cdb[14], fCcb->cdb[15],
 						fCcb->cdb_length);
+				}
+
 				fCcb->device_status = SCSI_STATUS_CHECK_CONDITION;
 			} else {
 				// TODO ATA error handling goes here
diff --git a/src/add-ons/kernel/busses/scsi/ahci/sata_request.h b/src/add-ons/kernel/busses/scsi/ahci/sata_request.h
index 71532ab9ad..f1efcf271f 100644
--- a/src/add-ons/kernel/busses/scsi/ahci/sata_request.h
+++ b/src/add-ons/kernel/busses/scsi/ahci/sata_request.h
@@ -6,6 +6,7 @@
 #define _SATA_REQUEST_H
 
 #include "ahci_defs.h"
+#include "scsi_cmds.h"
 
 class sata_request
 {
@@ -22,6 +23,7 @@ public:
 
 	void			set_atapi_cmd(size_t transferLength);
 	bool 			is_atapi();
+	bool			is_test_unit_ready();
 
 	scsi_ccb *		ccb();
 	const void *	fis();
@@ -65,6 +67,13 @@ sata_request::is_atapi()
 }
 
 
+inline bool
+sata_request::is_test_unit_ready()
+{
+	return fIsATAPI && fCcb != NULL && fCcb->cdb[0] == SCSI_OP_TEST_UNIT_READY;
+}
+
+
 inline void *
 sata_request::data()
 {