diff --git a/roles/buildbot/files/packages.py b/roles/buildbot/files/packages.py
index a26da0f..51877e3 100644
--- a/roles/buildbot/files/packages.py
+++ b/roles/buildbot/files/packages.py
@@ -110,6 +110,13 @@ def branchToFalterBranch(props):
     }
     return o2f.get(props["branch"])
 
+@util.renderer
+def signCommand(props, wwwdir):
+    match props["branch"]:
+        case "main" | "testbuildbot":
+            return f'apk adbsign --allow-untrusted --sign-key apk.snapshot.PRIVATE.pem {wwwdir}/falter/packages.adb'
+        case _:
+            return f'signify-openbsd -S -m {wwwdir}/falter/Packages -s packagefeed_master.sec'
 
 # Fans out to one builder per arch and blocks for the results.
 def packagesFactory(f, wwwPrefix):
@@ -292,10 +299,7 @@ def packagesArchFactory(f, wwwPrefix, wwwURL, alpineVersion):
             command=[
                 "sh",
                 "-c",
-                util.Interpolate(
-                    "signify-openbsd -S -m %(kw:wwwdir)s/falter/Packages -s packagefeed_master.sec",
-                    wwwdir=wwwdir,
-                ),
+                signCommand.withArgs(wwwdir)
             ],
         )
     )