def readB423Header(hdrStr: str):
    """Read B423 header for a single Lemi B423 file
    
    Parameters
    ----------
    hdrStr : str
        The headers as a string
    
    Returns
    -------
    dict 
        A dictionary of header values
    """
    hdr = hdrStr.decode()
    hdr = hdr.split('\r\n')
    headers = dict()
    for idx, h in enumerate(hdr):
        hdr[idx] = h.replace('%', '')
        if '=' in h:
            sp = hdr[idx].split('=')
            key = sp[0].strip()
            value = float(sp[1].strip())
            headers[key] = value
        if 'Lat' in h or 'Lon' in h or 'Alt' in h:
            key = hdr[idx][0:3]
            value = hdr[idx][3:].strip()
            headers[key] = value
    return headers
