diff --git a/debian/patches/fix-probing-of-large-block-devices.patch b/debian/patches/fix-probing-of-large-block-devices.patch
new file mode 100644
index 0000000..6ff2405
--- /dev/null
+++ b/debian/patches/fix-probing-of-large-block-devices.patch
@@ -0,0 +1,24 @@
+Description: fix size probing of large block devices.
+Author: Vangelis Koukis <vkoukis@gmail.com>
+Last-Update: 2014-08-03
+Index: dcfldd-1.3.4.1/sizeprobe.c
+===================================================================
+--- dcfldd-1.3.4.1.orig/sizeprobe.c
++++ dcfldd-1.3.4.1/sizeprobe.c
+@@ -63,9 +63,13 @@ static off_t midpoint(off_t a, off_t b,
+ static off_t get_dev_size(int fd, long blksize) 
+ {
+     off_t num_sectors = 0;
+-  
+-    if (ioctl(fd, BLKGETSIZE, &num_sectors))
+-        log_info("%s: ioctl call to BLKGETSIZE failed.\n", program_name);
++
++    /*
++     * Use BLKGETSIZE64 unconditionally, since dcfldd.h #defines _FILE_OFFSET_BITS 64
++     * and off_t is guaranteed to be large enough to hold the result.
++     */
++    if (ioctl(fd, BLKGETSIZE64, &num_sectors))
++        log_info("%s: ioctl call to BLKGETSIZE64 failed.\n", program_name);
+     else 
+         return (num_sectors * 512);
+ }
diff --git a/debian/patches/fix-sizeprobe-option.patch b/debian/patches/fix-sizeprobe-option.patch
new file mode 100644
index 0000000..d20c485
--- /dev/null
+++ b/debian/patches/fix-sizeprobe-option.patch
@@ -0,0 +1,16 @@
+Description: fix the sizeprobe=of option.
+Author: Vangelis Koukis <vkoukis@gmail.com>
+Last-Update: 2014-08-03
+Index: dcfldd-1.3.4.1/dcfldd.c
+===================================================================
+--- dcfldd-1.3.4.1.orig/dcfldd.c
++++ dcfldd-1.3.4.1/dcfldd.c
+@@ -759,7 +759,7 @@ int main(int argc, char **argv)
+         else
+             sizeprobe(STDIN_FILENO);
+     else if (probe == PROBE_OUTPUT)
+-        sizeprobe(STDOUT_FILENO);
++        sizeprobe(outputlist->data.fd);
+     start_time = time(NULL);
+     
+     if (do_verify)