diff --git a/pungi/phases/image_build.py b/pungi/phases/image_build.py
index cb76c1aa..cd034cd2 100644
--- a/pungi/phases/image_build.py
+++ b/pungi/phases/image_build.py
@@ -22,10 +22,13 @@ from productmd.rpms import Rpms
 # This is a mapping from formats to file extensions. The format is what koji
 # image-build command expects as argument, and the extension is what the file
 # name will be ending with. The extensions are used to filter out which task
-# results will be pulled into the compose.
+# results will be pulled into the compose. This dict is also used later in
+# the process to set the image 'type' in productmd metadata terms - the type
+# is set as the first key in this dict which has the file's extension in its
+# values. This dict is imported and extended for similar purposes by other
+# phases (at least osbuild and kiwibuild).
 EXTENSIONS = {
     "docker": ["tar.gz", "tar.xz"],
-    "iso": ["iso"],
     "liveimg-squashfs": ["liveimg.squashfs"],
     "qcow": ["qcow"],
     "qcow2": ["qcow2"],
@@ -40,7 +43,6 @@ EXTENSIONS = {
     "vdi": ["vdi"],
     "vmdk": ["vmdk"],
     "vpc": ["vhd"],
-    "vhd-compressed": ["vhd.gz", "vhd.xz"],
     "vsphere-ova": ["vsphere.ova"],
 }
 
diff --git a/pungi/phases/kiwibuild.py b/pungi/phases/kiwibuild.py
index bb268125..15732cea 100644
--- a/pungi/phases/kiwibuild.py
+++ b/pungi/phases/kiwibuild.py
@@ -15,6 +15,10 @@ KIWIEXTENSIONS = [
     ("vhd-compressed", ["vhdfixed.xz"], "vhd.xz"),
     ("vagrant-libvirt", ["vagrant.libvirt.box"], "vagrant-libvirt.box"),
     ("vagrant-virtualbox", ["vagrant.virtualbox.box"], "vagrant-virtualbox.box"),
+    # .iso images can be of many types - boot, cd, dvd, live... -
+    # so 'boot' is just a default guess. 'iso' is not a valid
+    # productmd image type
+    ("boot", [".iso"], "iso"),
 ]
 
 
diff --git a/pungi/phases/osbuild.py b/pungi/phases/osbuild.py
index 6c5b7e5a..a3b5c9b8 100644
--- a/pungi/phases/osbuild.py
+++ b/pungi/phases/osbuild.py
@@ -11,6 +11,16 @@ from ..linker import Linker
 from ..wrappers import kojiwrapper
 from .image_build import EXTENSIONS
 
+# copy and modify EXTENSIONS with some that osbuild produces but which
+# do not exist as `koji image-build` formats
+OSBUILDEXTENSIONS = EXTENSIONS.copy()
+OSBUILDEXTENSIONS.update(
+    {
+        "iso": ["iso"],
+        "vhd-compressed": ["vhd.gz", "vhd.xz"],
+    }
+)
+
 
 class OSBuildPhase(
     base.PhaseLoggerMixin, base.ImageConfigMixin, base.ConfigGuardedPhase
@@ -203,7 +213,7 @@ class RunOSBuildThread(WorkerThread):
         # architecture, but we don't verify that.
         build_info = koji.koji_proxy.getBuild(build_id)
         for archive in koji.koji_proxy.listArchives(buildID=build_id):
-            if archive["type_name"] not in EXTENSIONS:
+            if archive["type_name"] not in OSBUILDEXTENSIONS:
                 # Ignore values that are not of required types.
                 continue
 
@@ -241,7 +251,7 @@ class RunOSBuildThread(WorkerThread):
 
             linker.link(src_file, image_dest, link_type=compose.conf["link_type"])
 
-            for suffix in EXTENSIONS[archive["type_name"]]:
+            for suffix in OSBUILDEXTENSIONS[archive["type_name"]]:
                 if archive["filename"].endswith(suffix):
                     break
             else: