diff -Nru yt-3.4.0/debian/changelog yt-3.4.0/debian/changelog
--- yt-3.4.0/debian/changelog	2017-10-21 13:55:11.000000000 +0000
+++ yt-3.4.0/debian/changelog	2017-10-24 16:11:30.000000000 +0000
@@ -1,3 +1,9 @@
+yt (3.4.0-3) unstable; urgency=low
+
+  * Fix 32 bit FTBF.  Closes: #879482
+
+ -- BW Keller <malzraa@gmail.com>  Tue, 24 Oct 2017 16:11:30 +0000
+
 yt (3.4.0-2) unstable; urgency=low
 
   * Fix build issue with home directory needed for nose tests.
diff -Nru yt-3.4.0/debian/patches/fix_32bit_ftbfs.patch yt-3.4.0/debian/patches/fix_32bit_ftbfs.patch
--- yt-3.4.0/debian/patches/fix_32bit_ftbfs.patch	2017-10-15 12:33:30.000000000 +0000
+++ yt-3.4.0/debian/patches/fix_32bit_ftbfs.patch	2017-10-24 16:11:30.000000000 +0000
@@ -11,3 +11,29 @@
      cdef np.ndarray[np.float64_t, ndim=2] xyz, rztheta, ptemp, b1, b2, dsect
  
      # set up  points
+@@ -201,12 +201,12 @@
+     tsect, dsect = _cart_intersect(p1cart, p2cart, _cyl2cart(b1), _cyl2cart(b2))
+     tmask = np.logical_and(0.0<=tsect, tsect<=1.0)
+     ret = np.unique(tsect[tmask], return_index=True)
+-    tsect, tinds = ret[0], ret[1].astype('int64')
++    tsect, tinds = ret[0], ret[1].astype('int')
+     inds = inds[tmask][tinds]
+     xyz = dsect[tmask][tinds]
+     s = np.sqrt(((xyz - p1cart) * (xyz - p1cart)).sum(axis=1))
+     ret = np.unique(s, return_index=True)
+-    s, sinds = ret[0], ret[1].astype('int64')
++    s, sinds = ret[0], ret[1].astype('int')
+     inds = inds[sinds]
+     xyz = xyz[sinds]
+     t = s/np.sqrt((dpcart*dpcart).sum())
+--- a/yt/utilities/lib/misc_utilities.pyx
++++ b/yt/utilities/lib/misc_utilities.pyx
+@@ -437,7 +437,7 @@
+     cdef np.float64_t z0
+     alpha = np.zeros(4)
+     #the sources must be ordered along z to avoid edges when two overlap
+-    idx = np.argsort(zs)
++    idx = np.asarray(np.argsort(zs), dtype='int64')
+     for j in idx:
+         r = radii[j]
+         r2 = int((r+0.3)*(r+0.3))  #0.3 to get nicer shape