Reading received packets in didUpdateValueForCharacteristic - ios

Question

I need to read the received bytes and parse them with a custom method, which basically goes through bytes and skips every 0x7D (or a } ). But what happens now is that it does that for only one received packet, and I dont know why that is happening since im calling my method in didUpdateValueForCharacteristic :
- (void) peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error
{
if (error)
{
NSLog(#"Error receiving notification for characteristic %#: %#", characteristic, error);
return;
}
NSLog(#"Received data on a characteristic.");
if (characteristic == self.rxCharacteristic)
{
self.bluetoothData = [[NSMutableData alloc] initWithData:[characteristic value]];
[self unstuff1:[characteristic value]];
NSLog(#"First NSDAta %#", self.bluetoothData);
[self unstuff1:self.bluetoothData];
NSLog(#"Parsed First NSDATA %#", self.bluetoothData);
NSString *stringForPrintingOutToConsole = [[NSString alloc] initWithData:self.bluetoothData encoding:NSASCIIStringEncoding];
[self.delegate didReceiveData:stringForPrintingOutToConsole];
}
else if ([characteristic.UUID isEqual:self.class.hardwareRevisionStringUUID])
{
NSString *hwRevision = #"";
const uint8_t *bytes = characteristic.value.bytes;
for (int i = 0; i < characteristic.value.length; i++)
{
NSLog(#"%x", bytes[i]);
hwRevision = [hwRevision stringByAppendingFormat:#"0x%02x, ", bytes[i]];
}
// this one reads the hardware revision
[self.delegate didReadHardwareRevisionString:[hwRevision substringToIndex:hwRevision.length-2]];
}
}
and a custom method for parsing :
- (NSMutableData *)unstuff1:(NSMutableData *)mutableData {
NSUInteger dataLength = [self.bluetoothData length];
unsigned char *bytes = [self.bluetoothData bytes];
uint16_t i, j = 0;
for (int i = 0; i < dataLength; i++)
{
if (bytes[i] == 0x7D)
{
bytes[j] = bytes[i+1] ^ 0x20;
i++;
} else
{
bytes[j] = bytes[i];
j++;
}
}
return mutableData;
}
if anyone has a clue, i'd highly appreciate help.