This is UI side unreadable device support.

chrome/browser/resources/file_manager/css/file_manager.css

Index: chrome/browser/resources/file_manager/css/file_manager.css
diff --git a/chrome/browser/resources/file_manager/css/file_manager.css b/chrome/browser/resources/file_manager/css/file_manager.css
index 16316e3a33618d3978ae4961aeb0c18fbf637352..1071a31d0d4e4b28d422db59aab1e204962e06d1 100644
--- a/chrome/browser/resources/file_manager/css/file_manager.css
+++ b/chrome/browser/resources/file_manager/css/file_manager.css
@@ -325,6 +325,10 @@ li.thumbnail-item[selected] .file-checkbox {
   background-image: url(../images/filetype_audio.png);
 }
 
+.detail-icon[iconType="device"] {
+  background-image: url(../images/filetype_device.png);
+}
+
 .detail-icon[iconType="doc"] {
   background-image: url(../images/filetype_doc.png);
 }
@@ -357,6 +361,10 @@ li.thumbnail-item[selected] .file-checkbox {
   background-image: url(../images/filetype_text.png);
 }
 
+.detail-icon[iconType="unreadable"] {
+  background-image: url(../images/filetype_unreadable_device.png);
+}
+
 .detail-icon[iconType="video"] {
   background-image: url(../images/filetype_video.png);
 }