diff -up libpciaccess-0.10.6/src/linux_devmem.c.jx libpciaccess-0.10.6/src/linux_devmem.c
--- libpciaccess-0.10.6/src/linux_devmem.c.jx	2008-10-15 18:35:54.000000000 -0400
+++ libpciaccess-0.10.6/src/linux_devmem.c	2009-08-05 11:43:14.000000000 -0400
@@ -50,6 +50,30 @@
 #include "pciaccess_private.h"
 #include "linux_devmem.h"
 
+static int
+rom_sanity_check(struct pci_device *info, void *buffer)
+{
+    unsigned char *bios = buffer;
+    int offset;
+    unsigned short vendor, device;
+
+    if (bios[0] != 0x55 || bios[1] != 0xAA)
+        return 0;
+
+    offset = (bios[0x19] << 8) + bios[0x18];
+
+    if (bios[offset] != 'P' ||
+       bios[offset+1] != 'C' ||
+       bios[offset+2] != 'I' ||
+       bios[offset+3] != 'R')
+       return 0;
+
+    vendor = (bios[offset+5] << 8) + bios[offset+4];
+    device = (bios[offset+7] << 8) + bios[offset+6];
+
+    return (info->vendor_id == vendor) && (info->device_id == device);
+}
+
 /**
  * Read a device's expansion ROM using /dev/mem.
  * 
@@ -152,5 +176,5 @@ pci_device_linux_devmem_read_rom(struct 
 	}
     }
 
-    return err;
+    return !rom_sanity_check(dev, buffer);
 }