diff --git a/dummyflasher.c b/dummyflasher.c
index 4a4ea0f..3bda7a7 100644
--- a/dummyflasher.c
+++ b/dummyflasher.c
@@ -40,6 +40,19 @@
 	return 0;
 }
 
+void *dummy_map(const char *descr, unsigned long phys_addr, size_t len)
+{
+	printf("%s: Mapping %s, 0x%lx bytes at 0x%08lx\n",
+		__func__, descr, (unsigned long)len, phys_addr);
+	return (void *)phys_addr;
+}
+
+void dummy_unmap(void *virt_addr, size_t len)
+{
+	printf("%s: Unmapping 0x%lx bytes at %p\n",
+		__func__, (unsigned long)len, virt_addr);
+}
+
 void dummy_chip_writeb(uint8_t val, volatile void *addr)
 {
 	printf("%s: addr=%p, val=0x%02x\n", __func__, addr, val);
diff --git a/flash.h b/flash.h
index 5736516..2a11c24 100644
--- a/flash.h
+++ b/flash.h
@@ -87,6 +87,9 @@
 	int (*init) (void);
 	int (*shutdown) (void);
 
+	void * (*map_flash_region) (const char *descr, unsigned long phys_addr, size_t len);
+	void (*unmap_flash_region) (void *virt_addr, size_t len);
+
 	void (*chip_writeb) (uint8_t val, volatile void *addr);
 	void (*chip_writew) (uint16_t val, volatile void *addr);
 	void (*chip_writel) (uint32_t val, volatile void *addr);
@@ -107,6 +110,16 @@
 	return programmer_table[programmer].shutdown();
 }
 
+static inline void *programmer_map_flash_region(const char *descr, unsigned long phys_addr, size_t len)
+{
+	return programmer_table[programmer].map_flash_region(descr, phys_addr, len);
+}
+
+static inline void programmer_unmap_flash_region(void *virt_addr, size_t len)
+{
+	programmer_table[programmer].unmap_flash_region(virt_addr, len);
+}
+
 static inline void chip_writeb(uint8_t val, volatile void *addr)
 {
 	programmer_table[programmer].chip_writeb(val, addr);
@@ -579,6 +592,8 @@
 /* dummyflasher.c */
 int dummy_init(void);
 int dummy_shutdown(void);
+void *dummy_map(const char *descr, unsigned long phys_addr, size_t len);
+void dummy_unmap(void *virt_addr, size_t len);
 void dummy_chip_writeb(uint8_t val, volatile void *addr);
 void dummy_chip_writew(uint16_t val, volatile void *addr);
 void dummy_chip_writel(uint32_t val, volatile void *addr);
diff --git a/flashrom.c b/flashrom.c
index 981d835..e00789d 100644
--- a/flashrom.c
+++ b/flashrom.c
@@ -40,6 +40,8 @@
 	{
 		.init		= internal_init,
 		.shutdown	= internal_shutdown,
+		.map_flash_region	= physmap,
+		.unmap_flash_region	= physunmap,
 		.chip_readb	= internal_chip_readb,
 		.chip_readw	= internal_chip_readw,
 		.chip_readl	= internal_chip_readl,
@@ -51,6 +53,8 @@
 	{
 		.init		= dummy_init,
 		.shutdown	= dummy_shutdown,
+		.map_flash_region	= dummy_map,
+		.unmap_flash_region	= dummy_unmap,
 		.chip_readb	= dummy_chip_readb,
 		.chip_readw	= dummy_chip_readw,
 		.chip_readl	= dummy_chip_readl,
@@ -66,7 +70,7 @@
 {
 	size_t size = flash->total_size * 1024;
 	/* Flash registers live 4 MByte below the flash. */
-	flash->virtual_registers = physmap("flash chip registers", (0xFFFFFFFF - 0x400000 - size + 1), size);
+	flash->virtual_registers = programmer_map_flash_region("flash chip registers", (0xFFFFFFFF - 0x400000 - size + 1), size);
 }
 
 int read_memmapped(struct flashchip *flash, uint8_t *buf)
@@ -98,23 +102,8 @@
 
 		size = flash->total_size * 1024;
 
-		/* If getpagesize() > size -> 
-		 * "Can't mmap memory using /dev/mem: Invalid argument"
-		 * This should never happen as we don't support any flash chips
-		 * smaller than 4k or 8k (yet).
-		 */
-
-		if (getpagesize() > size) {
-			/*
-			 * if a flash size of 0 is mapped, we map a single page
-			 * so we can probe in that area whether we know the
-			 * vendor at least.
-			 */
-			size = getpagesize();
-		}
-
 		base = flashbase ? flashbase : (0xffffffff - size + 1);
-		flash->virtual_memory = physmap("flash chip", base, size);
+		flash->virtual_memory = programmer_map_flash_region("flash chip", base, size);
 
 		if (force)
 			break;
@@ -127,7 +116,8 @@
 			break;
 
 notfound:
-		physunmap((void *)flash->virtual_memory, size);
+		/* The intermediate cast to unsigned long works around a gcc warning bug. */
+		programmer_unmap_flash_region((void *)(unsigned long)flash->virtual_memory, size);
 	}
 
 	if (!flash || !flash->name)
diff --git a/physmap.c b/physmap.c
index 49e1bfc..f1a68db 100644
--- a/physmap.c
+++ b/physmap.c
@@ -69,12 +69,33 @@
 
 void physunmap(void *virt_addr, size_t len)
 {
+	if (len == 0) {
+		printf_debug("Not unmapping zero size at %p\n", virt_addr);
+		return;
+	}
+		
 	munmap(virt_addr, len);
 }
 #endif
 
 void *physmap(const char *descr, unsigned long phys_addr, size_t len)
 {
+	if (len == 0) {
+		printf_debug("Not mapping %s, zero size at 0x%08lx\n",
+			descr, phys_addr);
+		return NULL;
+	}
+		
+	if ((getpagesize() - 1) & len) {
+		fprintf(stderr, "Mapping %s at 0x%08lx, unaligned size 0x%lx\n",
+			descr, phys_addr, (unsigned long)len);
+	}
+
+	if ((getpagesize() - 1) & phys_addr) {
+		fprintf(stderr, "Mapping %s, 0x%lx bytes at unaligned 0x%08lx\n",
+			descr, (unsigned long)len, phys_addr);
+	}
+
 	void *virt_addr = sys_physmap(phys_addr, len);
 
 	if (NULL == virt_addr) {