diff --git a/ChangeLog b/ChangeLog
index cb499bb01..16be610ea 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2011-01-22  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	* grub-core/disk/scsi.c (grub_scsi_read): Fix binary and check and make
+	logical expression more readable.
+
 2011-01-22  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* grub-core/disk/raid.c (insert_array): Ensure uniqueness of p->number
diff --git a/grub-core/disk/scsi.c b/grub-core/disk/scsi.c
index 902ab12c3..a40de278f 100644
--- a/grub-core/disk/scsi.c
+++ b/grub-core/disk/scsi.c
@@ -506,7 +506,7 @@ grub_scsi_read (grub_disk_t disk, grub_disk_addr_t sector,
   if (scsi->blocksize != GRUB_DISK_SECTOR_SIZE)
     {
       unsigned spb = scsi->blocksize >> GRUB_DISK_SECTOR_BITS;
-      if (! (spb != 0 && (scsi->blocksize & GRUB_DISK_SECTOR_SIZE) == 0))
+      if (spb == 0 || (scsi->blocksize & (GRUB_DISK_SECTOR_SIZE - 1)) != 0)
 	return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
 			   "unsupported SCSI block size");