diff --git a/Cargo.lock b/Cargo.lock
index 83480a7..0cecab2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -61,6 +61,18 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 
+[[package]]
+name = "bitvec"
+version = "0.19.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8942c8d352ae1838c9dda0b0ca2ab657696ef2232a20147cf1b30ae1a9cb4321"
+dependencies = [
+ "funty",
+ "radium",
+ "tap",
+ "wyz",
+]
+
 [[package]]
 name = "block-buffer"
 version = "0.9.0"
@@ -153,9 +165,9 @@ dependencies = [
 
 [[package]]
 name = "devd-rs"
-version = "0.3.1"
+version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1945ccb7caedabdfb9347766ead740fb1e0582b7425598325f546adbd832cce1"
+checksum = "471c3f7f2c67082daa3659ff7abce0818cde6b433fd64c5045c7f75108d11e6d"
 dependencies = [
  "libc",
  "nom",
@@ -206,6 +218,12 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "00b0228411908ca8685dba7fc2cdd70ec9990a6e753e89b6ac91a84c40fbaf4b"
 
+[[package]]
+name = "funty"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fed34cd105917e91daa4da6b3728c47b068749d6a62c59811f06ed2ac71d9da7"
+
 [[package]]
 name = "generic-array"
 version = "0.14.4"
@@ -311,16 +329,18 @@ dependencies = [
 
 [[package]]
 name = "memchr"
-version = "2.4.0"
+version = "2.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b16bd47d9e329435e309c58469fe0791c2d0d1ba96ec0954152a5ae2b04387dc"
+checksum = "0ee1c47aaa256ecabcaea351eae4a9b01ef39ed810004e298d2511ed284b1525"
 
 [[package]]
 name = "nom"
-version = "5.1.2"
+version = "6.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ffb4262d26ed83a1c0a33a38fe2bb15797329c85770da05e6b828ddb782627af"
+checksum = "9c5c51b9083a3c620fa67a2a635d1ce7d95b897e957d6b28ff9a5da960a103a6"
 dependencies = [
+ "bitvec",
+ "funty",
  "memchr",
  "version_check",
 ]
@@ -413,6 +433,12 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "radium"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "941ba9d78d8e2f7ce474c015eea4d9c6d25b6a3327f9832ee29a4de27f91bbb8"
+
 [[package]]
 name = "rand"
 version = "0.7.3"
@@ -521,9 +547,9 @@ checksum = "5d79b4b604167921892e84afbbaad9d5ad74e091bf6c511d9dbfb0593f09fabd"
 
 [[package]]
 name = "rust_util"
-version = "0.6.40"
+version = "0.6.41"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "38bab12142950cb1b14790648b024708f628908e90eeab1a1d38022fb3d52b2e"
+checksum = "df24005feacce81f4ae340464b39c380f7e01e7225bfdef62d40cb44cb1c11d7"
 dependencies = [
  "lazy_static",
  "libc",
@@ -604,6 +630,12 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "tap"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"
+
 [[package]]
 name = "term"
 version = "0.7.0"
@@ -746,3 +778,9 @@ name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
+[[package]]
+name = "wyz"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85e60b0d1b5f99db2556934e21937020776a5d31520bf169e851ac44e6420214"
diff --git a/src/register.rs b/src/register.rs
index 3a54e14..9a5ad7a 100644
--- a/src/register.rs
+++ b/src/register.rs
@@ -21,12 +21,15 @@ impl Command for CommandImpl {
     }
 
     fn run(&self, _arg_matches: &ArgMatches, sub_arg_matches: &ArgMatches) -> CommandError {
+        let json_output = sub_arg_matches.is_present("json");
+        if json_output {
+            rust_util::util_msg::set_logger_std_out(false);
+        }
         let app_id = sub_arg_matches.value_of("app-id").unwrap();
         let timeout_ms = match sub_arg_matches.value_of("timeout").unwrap().parse::<u32>() {
             Ok(t) => (t * 1000) as u64,
             Err(e) => return simple_error!("Timeout should be a number: {}", e),
         };
-        let json_output = sub_arg_matches.is_present("json");
 
         let u2fv2_challenge = U2fV2Challenge::new_random(app_id);
         let u2fv2_challenge_str = u2fv2_challenge.to_json();
@@ -65,7 +68,7 @@ impl Command for CommandImpl {
         match u2f_registration_data {
             Ok(data) => {
                 if json_output {
-                    success!("{}", serde_json::to_string_pretty(&data).unwrap());
+                    println!("{}", serde_json::to_string_pretty(&data).unwrap());
                 } else {
                     success!("Device info: {}", data.device_info);
                     if let Some(cert) = data.attestation_cert_pem {