diff --git a/atahpt.c b/atahpt.c
index f8be8c4..242e14a 100644
--- a/atahpt.c
+++ b/atahpt.c
@@ -69,6 +69,8 @@
 		return 1;
 
 	io_base_addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_4);
+	if (!io_base_addr)
+		return 1;
 
 	/* Enable flash access. */
 	reg32 = pci_read_long(dev, REG_FLASH_ACCESS);
diff --git a/drkaiser.c b/drkaiser.c
index 8c9fb6a..0cf1fdb 100644
--- a/drkaiser.c
+++ b/drkaiser.c
@@ -69,6 +69,8 @@
 		return 1;
 
 	addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_2);
+	if (!addr)
+		return 1;
 
 	/* Write magic register to enable flash write. */
 	rpci_write_word(dev, PCI_MAGIC_DRKAISER_ADDR, PCI_MAGIC_DRKAISER_VALUE);
diff --git a/gfxnvidia.c b/gfxnvidia.c
index 8f3aa44..d3ee14e 100644
--- a/gfxnvidia.c
+++ b/gfxnvidia.c
@@ -90,6 +90,9 @@
 		return 1;
 
 	io_base_addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_0);
+	if (!io_base_addr)
+		return 1;
+
 	io_base_addr += 0x300000;
 	msg_pinfo("Detected NVIDIA I/O base address: 0x%x.\n", io_base_addr);
 
diff --git a/nic3com.c b/nic3com.c
index 8d67b54..27e28c7 100644
--- a/nic3com.c
+++ b/nic3com.c
@@ -96,6 +96,8 @@
 		return 1;
 
 	io_base_addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_0);
+	if (!io_base_addr)
+		return 1;
 
 	id = dev->device_id;
 
diff --git a/nicintel.c b/nicintel.c
index 305657c..98ba29f 100644
--- a/nicintel.c
+++ b/nicintel.c
@@ -76,12 +76,17 @@
 		return 1;
 
 	addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_2);
+	if (!addr)
+		return 1;
+
 	nicintel_bar = rphysmap("Intel NIC flash", addr, NICINTEL_MEMMAP_SIZE);
 	if (nicintel_bar == ERROR_PTR)
 		return 1;
 
 	addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_0);
-	/* FIXME: This is not an aligned mapping. Use 4k? */
+	if (!addr)
+		return 1;
+
 	nicintel_control_bar = rphysmap("Intel NIC control/status reg", addr, NICINTEL_CONTROL_MEMMAP_SIZE);
 	if (nicintel_control_bar == ERROR_PTR)
 		return 1;
diff --git a/nicintel_spi.c b/nicintel_spi.c
index b1bce6a..11b26c7 100644
--- a/nicintel_spi.c
+++ b/nicintel_spi.c
@@ -173,6 +173,9 @@
 		return 1;
 
 	io_base_addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_0);
+	if (!io_base_addr)
+		return 1;
+
 	nicintel_spibar = rphysmap("Intel Gigabit NIC w/ SPI flash", io_base_addr, MEMMAP_SIZE);
 	/* Automatic restore of EECD on shutdown is not possible because EECD
 	 * does not only contain FLASH_WRITES_DISABLED|FLASH_WRITES_ENABLED,
diff --git a/nicnatsemi.c b/nicnatsemi.c
index d62a73f..cb8da6d 100644
--- a/nicnatsemi.c
+++ b/nicnatsemi.c
@@ -64,6 +64,8 @@
 		return 1;
 
 	io_base_addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_0);
+	if (!io_base_addr)
+		return 1;
 
 	/* The datasheet shows address lines MA0-MA16 in one place and MA0-MA15
 	 * in another. My NIC has MA16 connected to A16 on the boot ROM socket
diff --git a/nicrealtek.c b/nicrealtek.c
index fb8e9e1..02fbd39 100644
--- a/nicrealtek.c
+++ b/nicrealtek.c
@@ -69,6 +69,8 @@
 		return 1;
 
 	io_base_addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_0);
+	if (!io_base_addr)
+		return 1;
 
 	/* Beware, this ignores the vendor ID! */
 	switch (dev->device_id) {
diff --git a/ogp_spi.c b/ogp_spi.c
index 3aed6e8..f8f7b2d 100644
--- a/ogp_spi.c
+++ b/ogp_spi.c
@@ -131,6 +131,9 @@
 		return 1;
 
 	io_base_addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_0);
+	if (!io_base_addr)
+		return 1;
+
 	ogp_spibar = rphysmap("OGP registers", io_base_addr, 4096);
 	if (ogp_spibar == ERROR_PTR)
 		return 1;
diff --git a/pcidev.c b/pcidev.c
index c7e9d78..3a3f77c 100644
--- a/pcidev.c
+++ b/pcidev.c
@@ -94,7 +94,7 @@
 
 	supported_cycles = pci_read_word(dev, PCI_COMMAND);
 
-	msg_pdbg("Requested BAR is ");
+	msg_pdbg("Requested BAR is of type ");
 	switch (bartype) {
 	case TYPE_MEMBAR:
 		msg_pdbg("MEM");
diff --git a/satamv.c b/satamv.c
index b44e1cf..3065f0c 100644
--- a/satamv.c
+++ b/satamv.c
@@ -88,6 +88,9 @@
 		return 1;
 
 	addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_0);
+	if (!addr)
+		return 1;
+
 	mv_bar = rphysmap("Marvell 88SX7042 registers", addr, 0x20000);
 	if (mv_bar == ERROR_PTR)
 		return 1;
@@ -136,6 +139,9 @@
 
 	/* Get I/O BAR location. */
 	tmp = pcidev_readbar(dev, PCI_BASE_ADDRESS_2);
+	if (!addr)
+		return 1;
+
 	/* Truncate to reachable range.
 	 * FIXME: Check if the I/O BAR is actually reachable.
 	 * This is an arch specific check.
diff --git a/satasii.c b/satasii.c
index 37266eb..83dc62c 100644
--- a/satasii.c
+++ b/satasii.c
@@ -85,9 +85,13 @@
 
 	if ((id == 0x3132) || (id == 0x3124)) {
 		addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_0);
+		if (!addr)
+			return 1;
 		reg_offset = 0x70;
 	} else {
 		addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_5);
+		if (!addr)
+			return 1;
 		reg_offset = 0x50;
 	}