diff --git a/platform/debian/koreader.desktop b/platform/debian/koreader.desktop
index c1d778763..b98bbc458 100644
--- a/platform/debian/koreader.desktop
+++ b/platform/debian/koreader.desktop
@@ -7,3 +7,7 @@ Terminal=false
 Type=Application
 Categories=Graphics;
 MimeType=application/pdf;application/x-cbz;application/epub+zip;image/vnd.djvu;text/plain;
+# Otherwise assumed incompatible with some mobile OSes
+# See <https://puri.sm/posts/specify-form-factors-in-your-librem-5-apps/>
+# and <https://github.com/koreader/koreader/issues/11118>
+X-Purism-FormFactor=Workstation;Mobile;