diff --git a/library/asn1write.c b/library/asn1write.c
index dd5a7455e..849e8c168 100644
--- a/library/asn1write.c
+++ b/library/asn1write.c
@@ -191,7 +191,7 @@ int mbedtls_asn1_write_bool( unsigned char **p, unsigned char *start, int boolea
     if( *p - start < 1 )
         return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
 
-    *--(*p) = (boolean) ? 1 : 0;
+    *--(*p) = (boolean) ? 255 : 0;
     len++;
 
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
diff --git a/tests/data_files/server1.key_usage.crt b/tests/data_files/server1.key_usage.crt
index 8a4c480c8..8f4e59f2d 100644
--- a/tests/data_files/server1.key_usage.crt
+++ b/tests/data_files/server1.key_usage.crt
@@ -10,11 +10,11 @@ CrFTxjB+FTms+Vruf5KepgVb5xOXhbUjktnUJAbVCSWJdQfdphqPPwkZvq1lLGTr
 lZvc/kFeF6babFtpzAK6FCwWJJxK3M3Q91Jnc/EtoCP9fvQxyi1wyokLBNsupk9w
 bp7OvViJ4lNZnm5akmXiiD8MlBmj3eXonZUT7Snbq3AS3FrKaxerUoJUsQIDAQAB
 o10wWzAJBgNVHRMEAjAAMB0GA1UdDgQWBBQfdNY/KcF0dEU7BRIsPai9Q1kCpjAf
-BgNVHSMEGDAWgBS0WuSls97SUva51aaVD+s+vMf9/zAOBgNVHQ8BAQEEBAMCAeAw
-DQYJKoZIhvcNAQEFBQADggEBAFd3JxNC2rEz94ProSZcv8NNk3e3Dhfms84qjkCM
-YhLyZCZywZ2cj3bXThNGVND81UNgqyzk/MEGfKh5d0EHD8v97H7Zvs/EN814d0UC
-/BZWlXqX9XInjxlI3baJrRWvsJJdRxMqub9LGBdhgZAtF1BVF9fk2QrV0GW6VN7a
-dGYdRYO80yf+vf5g41A0DIi3dhdLF1H7UPDwfUwkF5QckXw0yqueszcmxvCAnxng
-AUKoFS971WWCjCo8lMzOXOjeAwmibihT9XBabVzN1w3gOfSBbpHFi770bWgbKPWu
-csFKtvrXGtLVQeKkfI1lIMWWeddvkMWWBIqFrkBBLLOI4+A=
+BgNVHSMEGDAWgBS0WuSls97SUva51aaVD+s+vMf9/zAOBgNVHQ8BAf8EBAMCAeAw
+DQYJKoZIhvcNAQEFBQADggEBABKC/1x0m57EY4H412ue3ghCWgg07VcRKamnUSTs
+tnqI5T0mSvuPrxhINdQB6360ibctBkXP3S9rxGHiUdeK/JqxYs2YamCs50TSWpon
+p4Hzcmjsw1YgXsQ6pmYwkzU03zqs361gt7JSOzL2dN0IjwIy47qfLQb/AXhX2Ims
+7gBuqVpYqJuSHR0qsN/c6WgIE3IrbK1MB6CJTkxBfcSc5E4oUIBHmww+RSVLOczM
+nGk3U13dmfG0ndhMtrMyyxBZZSUwoZLjRZ6J5mHSv+k8oo1PYQeiivNEP53mgVaY
+ha0gLUIk6zNBRpY1uUmxQ+RQSMIyYPBb1RedHn2s8El2mlo=
 -----END CERTIFICATE-----