diff --git a/STATUS.md b/STATUS.md
index 08650c8b..f40beb54 100644
--- a/STATUS.md
+++ b/STATUS.md
@@ -251,7 +251,7 @@ Floating point mathematical routines - not official, but well known and broadly
 | `$BCF3`   | `FIN`                  | PARTIAL  | Only for 38k memory model + not fully tested yet   |
 | `$BD7E`   | `FINLOG`               | DONE     | From the Microsoft BASIC, original name: FINLOG    |
 | `$BDDD`   | `FOUT`                 | DONE     | From the Microsoft BASIC, original name: FOUT      |
-| `$BF71`   | `sqr_FAC1`             | PARTIAL  | needs `sqr_FAC2`                                   |
+| `$BF71`   | `sqr_FAC1`             | DONE     | From the Microsoft BASIC, original name: SQR       |
 | `$BF74`   | `sqr_FAC2`             | NOT DONE |                                                    |
 | `$BF78`   | `pwr_FAC2_MEM`         | PARTIAL  | needs `pwr_FAC2_FAC1`                              |
 | `$BF7B`   | `pwr_FAC2_FAC1`        | NOT DONE |                                                    |
diff --git a/src/basic/math_trans/bf71.sqr_FAC1.s b/src/basic/math_trans/bf71.sqr_FAC1.s
index 76f373ef..642feb3b 100644
--- a/src/basic/math_trans/bf71.sqr_FAC1.s
+++ b/src/basic/math_trans/bf71.sqr_FAC1.s
@@ -3,9 +3,13 @@
 ;; #LAYOUT# *   BASIC_0 #TAKE
 ;; #LAYOUT# *   *       #IGNORE
 
-;
+; This file is under the MIT license, it contains code released by Microsoft Corporation.
+; See LICENSE for more information.
+
 ; Math package - square root of FAC1
 ;
+; This is verified to be identical to the original Microsoft implementation where it was named SQR.
+;
 ; Note:
 ; - transfers FAC1 to FAC2 and falls through to SQR2
 ;
@@ -20,9 +24,9 @@
 
 sqr_FAC1:
 
-	jsr mov_FAC1_FAC2
+        jsr mov_r_FAC1_FAC2
 	
-	; FALLLTROUGH to sqr_FAC2
+        ; FALLLTROUGH to sqr_FAC2
 
 
 } else {
diff --git a/tools/similarity.c b/tools/similarity.c
index 77821498..15cb5bc3 100644
--- a/tools/similarity.c
+++ b/tools/similarity.c
@@ -20,7 +20,7 @@ int matches[MAX_SIZE];
 
 int phase_mask[MAX_SIZE+MAX_SIZE];
 
-#define NUM_CHUNKS 12
+#define NUM_CHUNKS 13
 // Pairs of start, end memory addresses of known exact similarity with the open source Microsoft BASIC
 unsigned short microsoft_basic_chunks[NUM_CHUNKS * 2] = {
     0xB391, 0xB39D,
@@ -31,6 +31,7 @@ unsigned short microsoft_basic_chunks[NUM_CHUNKS * 2] = {
     0xBD7E, 0xBD90,
     0xBDB3, 0xBDC1,
     0xBDDD, 0xBF51,
+    0xBF71, 0xBF73,
     0xBFB4, 0xBFEC,
     0xE043, 0xE08C,
     0xE264, 0xE2C2,     // Two byte gap here is an optimization