--- a/taskcluster/taskgraph/try_option_syntax.py
+++ b/taskcluster/taskgraph/try_option_syntax.py
@@ -119,17 +119,17 @@ UNITTEST_ALIASES = {
 }
 
 # unittest platforms can be specified by substring of the "pretty name", which
 # is basically the old Buildbot builder name.  This dict has {pretty name,
 # [test_platforms]} translations, This includes only the most commonly-used
 # substrings.  This is intended only for backward-compatibility.  New test
 # platforms should have their `test_platform` spelled out fully in try syntax.
 UNITTEST_PLATFORM_PRETTY_NAMES = {
-    'Ubuntu': ['linux', 'linux64', 'linux64-asan'],
+    'Ubuntu': ['linux32', 'linux64', 'linux64-asan'],
     'x64': ['linux64', 'linux64-asan'],
     'Android 4.3': ['android-4.3-arm7-api-15'],
     # other commonly-used substrings for platforms not yet supported with
     # in-tree taskgraphs:
     # '10.10': [..TODO..],
     # '10.10.5': [..TODO..],
     # '10.6': [..TODO..],
     # '10.8': [..TODO..],