diff --git a/m10/m10x.c b/m10/m10x.c
index 9a8adb5..c46a9f5 100644
--- a/m10/m10x.c
+++ b/m10/m10x.c
@@ -34,7 +34,7 @@ int option_verbose = 0,  // ausfuehrliche Anzeige
     option_res = 0,      // genauere Bitmessung
     option_color = 0,
     wavloaded = 0;
-int inv = 1;
+
 
 /* -------------------------------------------------------------------------- */
 /*
@@ -173,7 +173,6 @@ int read_bits_fsk(FILE *fp, int *bit, int *len) {
         y0 = sample;
         sample = read_signed_sample(fp);
         if (sample == EOF_INT) return EOF;
-        if (option_inv) sample = -sample; // 8bit: -sample-1
         sample_count++;
         par_alt = par;
         par =  (sample >= 0) ? 1 : -1;    // 8bit: 0..127,128..255 (-128..-1,0..127)
@@ -189,8 +188,8 @@ int read_bits_fsk(FILE *fp, int *bit, int *len) {
 
     *len = (int)(l+0.5);
 
-    if (inv > 0) *bit = (1+par_alt)/2;  // oben 1, unten -1
-    else         *bit = (1-par_alt)/2;  // sdr#<rev1381?, invers: unten 1, oben -1
+    if (!option_inv) *bit = (1+par_alt)/2;  // oben 1, unten -1
+    else             *bit = (1-par_alt)/2;  // sdr#<rev1381?, invers: unten 1, oben -1
 // *bit = (1+inv*par_alt)/2; // ausser inv=0
 
     /* Y-offset ? */
@@ -641,9 +640,6 @@ int main(int argc, char **argv) {
 
             if (!header_found) {
                 header_found = compare2();
-                if (header_found != 0) {
-                  inv = header_found;
-                }
             }
             else {
                 frame_rawbits[pos] = 0x30 + bit;  // Ascii