diff --git a/matter/src/cert/asn1_writer.rs b/matter/src/cert/asn1_writer.rs
index 3cb7f47..b3bb13c 100644
--- a/matter/src/cert/asn1_writer.rs
+++ b/matter/src/cert/asn1_writer.rs
@@ -17,7 +17,7 @@
 
 use super::{CertConsumer, MAX_DEPTH};
 use crate::error::Error;
-use chrono::{TimeZone, Utc};
+use chrono::{Datelike, TimeZone, Utc};
 use log::warn;
 
 #[derive(Debug)]
@@ -277,7 +277,13 @@ impl<'a> CertConsumer for ASN1Writer<'a> {
             }
         };
 
-        let time_str = format!("{}Z", dt.format("%y%m%d%H%M%S"));
-        self.write_str(0x17, time_str.as_bytes())
+        if dt.year() >= 2050 {
+            // If year is >= 2050, ASN.1 requires it to be Generalised Time
+            let time_str = format!("{}Z", dt.format("%Y%m%d%H%M%S"));
+            self.write_str(0x18, time_str.as_bytes())
+        } else {
+            let time_str = format!("{}Z", dt.format("%y%m%d%H%M%S"));
+            self.write_str(0x17, time_str.as_bytes())
+        }
     }
 }
diff --git a/matter/src/cert/mod.rs b/matter/src/cert/mod.rs
index 61d7bf2..b3f9338 100644
--- a/matter/src/cert/mod.rs
+++ b/matter/src/cert/mod.rs
@@ -668,7 +668,7 @@ impl<'a> CertVerifier<'a> {
         let k = KeyPair::new_from_public(parent.get_pubkey())?;
         k.verify_msg(asn1, self.cert.get_signature()).map_err(|e| {
             error!(
-                "Error in signature verification of certificate: {:#02x?}",
+                "Error in signature verification of certificate: {:x?}",
                 self.cert.get_subject_key_id()
             );
             e
@@ -706,7 +706,7 @@ pub trait CertConsumer {
 }
 
 const MAX_DEPTH: usize = 10;
-const MAX_ASN1_CERT_SIZE: usize = 800;
+const MAX_ASN1_CERT_SIZE: usize = 1000;
 
 mod asn1_writer;
 mod printer;
@@ -1025,8 +1025,8 @@ mod tests {
             0xbf, 0x68, 0x18, 0x59, 0x7f, 0xf7, 0xe8, 0xaf, 0x88, 0x91, 0x1c, 0x72, 0x32, 0xf7,
             0x52,
         ];
-        pub const ASN1_OUTPUT_TXT_IN_DN: [u8; 427] = [
-            0x30, 0x82, 0x01, 0xa7, 0xa0, 0x03, 0x02, 0x01, 0x02, 0x02, 0x01, 0x01, 0x30, 0x0a,
+        pub const ASN1_OUTPUT_TXT_IN_DN: [u8; 429] = [
+            0x30, 0x82, 0x01, 0xa9, 0xa0, 0x03, 0x02, 0x01, 0x02, 0x02, 0x01, 0x01, 0x30, 0x0a,
             0x06, 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x04, 0x03, 0x02, 0x30, 0x56, 0x31, 0x0b,
             0x30, 0x09, 0x06, 0x03, 0x55, 0x04, 0x06, 0x13, 0x02, 0x55, 0x53, 0x31, 0x0f, 0x30,
             0x0d, 0x06, 0x03, 0x55, 0x04, 0x0a, 0x0c, 0x06, 0x47, 0x6f, 0x6f, 0x67, 0x6c, 0x65,
@@ -1034,29 +1034,29 @@ mod tests {
             0x74, 0x65, 0x72, 0x20, 0x52, 0x6f, 0x6f, 0x74, 0x31, 0x20, 0x30, 0x1e, 0x06, 0x0a,
             0x2b, 0x06, 0x01, 0x04, 0x01, 0x82, 0xa2, 0x7c, 0x01, 0x04, 0x0c, 0x10, 0x46, 0x46,
             0x46, 0x46, 0x46, 0x46, 0x46, 0x45, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x31,
-            0x30, 0x1e, 0x17, 0x0d, 0x32, 0x31, 0x31, 0x32, 0x30, 0x38, 0x32, 0x30, 0x33, 0x30,
-            0x35, 0x35, 0x5a, 0x17, 0x0d, 0x32, 0x31, 0x31, 0x32, 0x30, 0x38, 0x32, 0x30, 0x33,
-            0x30, 0x35, 0x35, 0x5a, 0x30, 0x56, 0x31, 0x0b, 0x30, 0x09, 0x06, 0x03, 0x55, 0x04,
-            0x06, 0x13, 0x02, 0x55, 0x53, 0x31, 0x0f, 0x30, 0x0d, 0x06, 0x03, 0x55, 0x04, 0x0a,
-            0x0c, 0x06, 0x47, 0x6f, 0x6f, 0x67, 0x6c, 0x65, 0x31, 0x14, 0x30, 0x12, 0x06, 0x03,
-            0x55, 0x04, 0x03, 0x0c, 0x0b, 0x4d, 0x61, 0x74, 0x74, 0x65, 0x72, 0x20, 0x52, 0x6f,
-            0x6f, 0x74, 0x31, 0x20, 0x30, 0x1e, 0x06, 0x0a, 0x2b, 0x06, 0x01, 0x04, 0x01, 0x82,
-            0xa2, 0x7c, 0x01, 0x04, 0x0c, 0x10, 0x46, 0x46, 0x46, 0x46, 0x46, 0x46, 0x46, 0x45,
-            0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x31, 0x30, 0x59, 0x30, 0x13, 0x06, 0x07,
-            0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02, 0x01, 0x06, 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d,
-            0x03, 0x01, 0x07, 0x03, 0x42, 0x00, 0x04, 0x5b, 0x37, 0xdf, 0x65, 0x49, 0xc2, 0x0d,
-            0xc8, 0xd7, 0x22, 0xa6, 0xb8, 0xac, 0xb6, 0x60, 0xa8, 0xa7, 0x64, 0xce, 0x7b, 0xaf,
-            0x6c, 0x6c, 0x22, 0x4f, 0x7e, 0xe8, 0x43, 0x49, 0x68, 0x4a, 0xd7, 0xd8, 0x09, 0xff,
-            0x65, 0x00, 0x33, 0xd1, 0x52, 0x7d, 0xcf, 0x1f, 0xba, 0xac, 0x6a, 0x9c, 0x3a, 0xd8,
-            0xb4, 0x1e, 0xda, 0xc9, 0x09, 0xf7, 0xb5, 0xc7, 0x60, 0xfd, 0x54, 0x2c, 0x89, 0x23,
-            0x75, 0xa3, 0x66, 0x30, 0x64, 0x30, 0x12, 0x06, 0x03, 0x55, 0x1d, 0x13, 0x01, 0x01,
-            0xff, 0x04, 0x08, 0x30, 0x06, 0x01, 0x01, 0xff, 0x02, 0x01, 0x01, 0x30, 0x0e, 0x06,
-            0x03, 0x55, 0x1d, 0x0f, 0x01, 0x01, 0xff, 0x04, 0x04, 0x03, 0x02, 0x01, 0x06, 0x30,
-            0x1d, 0x06, 0x03, 0x55, 0x1d, 0x0e, 0x04, 0x16, 0x04, 0x14, 0x72, 0xc2, 0x01, 0xf7,
-            0x57, 0x19, 0x13, 0xb3, 0x48, 0xca, 0x00, 0xca, 0x7b, 0x45, 0xf4, 0x77, 0x46, 0x68,
-            0xc9, 0x7e, 0x30, 0x1f, 0x06, 0x03, 0x55, 0x1d, 0x23, 0x04, 0x18, 0x30, 0x16, 0x80,
-            0x14, 0x72, 0xc2, 0x01, 0xf7, 0x57, 0x19, 0x13, 0xb3, 0x48, 0xca, 0x00, 0xca, 0x7b,
-            0x45, 0xf4, 0x77, 0x46, 0x68, 0xc9, 0x7e,
+            0x30, 0x20, 0x17, 0x0d, 0x32, 0x31, 0x31, 0x32, 0x30, 0x38, 0x32, 0x30, 0x33, 0x30,
+            0x35, 0x35, 0x5a, 0x18, 0x0f, 0x32, 0x31, 0x32, 0x31, 0x31, 0x32, 0x30, 0x38, 0x32,
+            0x30, 0x33, 0x30, 0x35, 0x35, 0x5a, 0x30, 0x56, 0x31, 0x0b, 0x30, 0x09, 0x06, 0x03,
+            0x55, 0x04, 0x06, 0x13, 0x02, 0x55, 0x53, 0x31, 0x0f, 0x30, 0x0d, 0x06, 0x03, 0x55,
+            0x04, 0x0a, 0x0c, 0x06, 0x47, 0x6f, 0x6f, 0x67, 0x6c, 0x65, 0x31, 0x14, 0x30, 0x12,
+            0x06, 0x03, 0x55, 0x04, 0x03, 0x0c, 0x0b, 0x4d, 0x61, 0x74, 0x74, 0x65, 0x72, 0x20,
+            0x52, 0x6f, 0x6f, 0x74, 0x31, 0x20, 0x30, 0x1e, 0x06, 0x0a, 0x2b, 0x06, 0x01, 0x04,
+            0x01, 0x82, 0xa2, 0x7c, 0x01, 0x04, 0x0c, 0x10, 0x46, 0x46, 0x46, 0x46, 0x46, 0x46,
+            0x46, 0x45, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x31, 0x30, 0x59, 0x30, 0x13,
+            0x06, 0x07, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02, 0x01, 0x06, 0x08, 0x2a, 0x86, 0x48,
+            0xce, 0x3d, 0x03, 0x01, 0x07, 0x03, 0x42, 0x00, 0x04, 0x5b, 0x37, 0xdf, 0x65, 0x49,
+            0xc2, 0x0d, 0xc8, 0xd7, 0x22, 0xa6, 0xb8, 0xac, 0xb6, 0x60, 0xa8, 0xa7, 0x64, 0xce,
+            0x7b, 0xaf, 0x6c, 0x6c, 0x22, 0x4f, 0x7e, 0xe8, 0x43, 0x49, 0x68, 0x4a, 0xd7, 0xd8,
+            0x09, 0xff, 0x65, 0x00, 0x33, 0xd1, 0x52, 0x7d, 0xcf, 0x1f, 0xba, 0xac, 0x6a, 0x9c,
+            0x3a, 0xd8, 0xb4, 0x1e, 0xda, 0xc9, 0x09, 0xf7, 0xb5, 0xc7, 0x60, 0xfd, 0x54, 0x2c,
+            0x89, 0x23, 0x75, 0xa3, 0x66, 0x30, 0x64, 0x30, 0x12, 0x06, 0x03, 0x55, 0x1d, 0x13,
+            0x01, 0x01, 0xff, 0x04, 0x08, 0x30, 0x06, 0x01, 0x01, 0xff, 0x02, 0x01, 0x01, 0x30,
+            0x0e, 0x06, 0x03, 0x55, 0x1d, 0x0f, 0x01, 0x01, 0xff, 0x04, 0x04, 0x03, 0x02, 0x01,
+            0x06, 0x30, 0x1d, 0x06, 0x03, 0x55, 0x1d, 0x0e, 0x04, 0x16, 0x04, 0x14, 0x72, 0xc2,
+            0x01, 0xf7, 0x57, 0x19, 0x13, 0xb3, 0x48, 0xca, 0x00, 0xca, 0x7b, 0x45, 0xf4, 0x77,
+            0x46, 0x68, 0xc9, 0x7e, 0x30, 0x1f, 0x06, 0x03, 0x55, 0x1d, 0x23, 0x04, 0x18, 0x30,
+            0x16, 0x80, 0x14, 0x72, 0xc2, 0x01, 0xf7, 0x57, 0x19, 0x13, 0xb3, 0x48, 0xca, 0x00,
+            0xca, 0x7b, 0x45, 0xf4, 0x77, 0x46, 0x68, 0xc9, 0x7e,
         ];
     }
 }