From 02bc43b094e212c52075c69c9aa71003121596ce Mon Sep 17 00:00:00 2001
From: Sebastien Mondet <seb@mondet.org>
Date: Wed, 10 Oct 2018 19:19:02 -0400
Subject: [PATCH] Target only USB ledger with interface number 0

---
 src/lib_signer_backends/ledger.ml | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/lib_signer_backends/ledger.ml b/src/lib_signer_backends/ledger.ml
index b817a2291..732b1eac0 100644
--- a/src/lib_signer_backends/ledger.ml
+++ b/src/lib_signer_backends/ledger.ml
@@ -304,12 +304,18 @@ let find_ledgers ?id () =
   log_info "Found %d Ledger(s)" (List.length ledgers) ;
   filter_map_s begin fun device_info ->
     log_info "Processing Ledger at path [%s]" device_info.Hidapi.path ;
-    match Hidapi.(open_path device_info.path) with
-    | None -> return_none
-    | Some h ->
-        Lwt.finalize
-          (fun () -> Ledger.of_hidapi ?id device_info h)
-          (fun () -> Hidapi.close h ; Lwt.return_unit)
+    if device_info.Hidapi.interface_number <> 0
+    then
+      (* HID interfaces get number 0:
+         https://github.com/LedgerHQ/ledger-nano-s/issues/48 *)
+      return_none
+    else
+      match Hidapi.(open_path device_info.path) with
+      | None -> return_none
+      | Some h ->
+          Lwt.finalize
+            (fun () -> Ledger.of_hidapi ?id device_info h)
+            (fun () -> Hidapi.close h ; Lwt.return_unit)
   end ledgers
 
 let with_ledger id f =