FECModem: set byte to 0 (frownie symbol) if it contained an uncorrectable error

2 files changed, 9 insertions, 7 deletions

diff --git a/src/fecmodem.cc b/src/fecmodem.cc
index 5323135..bd0d58c 100644
--- a/src/fecmodem.cc
+++ b/src/fecmodem.cc
@@ -17,14 +17,16 @@ uint8_t FECModem::correct128(uint8_t *byte, uint8_t err)
 	uint8_t result = pgm_read_byte(&hammingParityCheck[err & 0x0f]);
 
 	if (result != NO_ERROR) {
-		if (result == UNCORRECTABLE || byte == NULL) {
+		if (byte == NULL)
 			return 3;
-		} else {
-			if (result != ERROR_IN_PARITY) {
-				*byte ^= result;
-			}
-			return 1;
+		if (result == UNCORRECTABLE) {
+			*byte = 0;
+			return 3;
+		}
+		if (result != ERROR_IN_PARITY) {
+			*byte ^= result;
 		}
+		return 1;
 	}
 	return 0;
 }
diff --git a/src/font.h b/src/font.h
index a705d57..b0015b3 100644
--- a/src/font.h
+++ b/src/font.h
@@ -133,7 +133,7 @@ const unsigned char PROGMEM chr_125[] = {0x03,0x41,0x36,0x08}; // }
 const unsigned char PROGMEM chr_126[] = {0x05,0x08,0x10,0x08,0x04,0x08}; // ~
 
 const glyph_t font[] PROGMEM = {
-	chr_001,
+	chr_002, // special character for uncorrectable byte errors
 	chr_001,
 	chr_002,
 	chr_003,