diff --git a/docs/source/release_notes.rst b/docs/source/release_notes.rst
index 42ce5ead..d48282ca 100644
--- a/docs/source/release_notes.rst
+++ b/docs/source/release_notes.rst
@@ -46,6 +46,8 @@ Availability: `AutomationHub`_, `Galaxy`_, `GitHub`_
 * Increased the minimum version of zhmcclient to 1.13.3 to pick up fixes and
   performance improvements. (related to issue #904)
 
+* Fixed readable attribute error when ensuring ISO mounted onto the partition. (related to issue #932)
+
 **Enhancements:**
 
 * Added a new make target 'end2end_show' to show the HMCs defined for end2end
diff --git a/plugins/modules/zhmc_partition.py b/plugins/modules/zhmc_partition.py
index b8692268..2da1bd6e 100644
--- a/plugins/modules/zhmc_partition.py
+++ b/plugins/modules/zhmc_partition.py
@@ -2059,7 +2059,7 @@ def ensure_iso_mount(params, check_mode):
             try:
                 with open(image_file, 'rb') as fp:
                     if not check_mode:
-                        image = fp.readall()
+                        image = fp.read()
             except IOError as exc:
                 raise ImageError(
                     "Cannot open ISO image file {fn!r} for reading: {exc}".