diff --git a/apps/grgsm_scanner b/apps/grgsm_scanner
index acd48d9..1688310 100755
--- a/apps/grgsm_scanner
+++ b/apps/grgsm_scanner
@@ -220,7 +220,7 @@
         # correction of central frequency
         # if the receiver has large frequency offset
         # the value of this variable should be set close to that offset in ppm
-        self.rtlsdr_source.set_freq_corr(options.ppm, 0)
+        self.rtlsdr_source.set_freq_corr(ppm, 0)
 
         self.rtlsdr_source.set_dc_offset_mode(2, 0)
         self.rtlsdr_source.set_iq_balance_mode(0, 0)
@@ -230,7 +230,7 @@
         self.head = blocks.head(gr.sizeof_gr_complex * 1, int(rec_len * sample_rate))
 
         # shift again by -0.1MHz in order to align channel center in 0Hz
-        self.blocks_rotator_cc = blocks.rotator_cc(-2 * pi * 0.1e6 / options.samp_rate)
+        self.blocks_rotator_cc = blocks.rotator_cc(-2 * pi * 0.1e6 / sample_rate)
 
         self.wideband_receiver = wideband_receiver(OSR=4, fc=carrier_frequency, samp_rate=sample_rate)
         self.gsm_extract_system_info = grgsm.extract_system_info()
diff --git a/lib/demapping/tch_f_chans_demapper_impl.cc b/lib/demapping/tch_f_chans_demapper_impl.cc
index a672b24..53f46fb 100644
--- a/lib/demapping/tch_f_chans_demapper_impl.cc
+++ b/lib/demapping/tch_f_chans_demapper_impl.cc
@@ -87,7 +87,7 @@
 
             new_hdr->sub_type = GSMTAP_CHANNEL_TCH_F;
             if (fn_mod13 == 12)
-                header->sub_type = GSMTAP_CHANNEL_ACCH|GSMTAP_CHANNEL_TCH_F;
+                new_hdr->sub_type = GSMTAP_CHANNEL_ACCH|GSMTAP_CHANNEL_TCH_F;
 
             pmt::pmt_t msg_binary_blob = pmt::make_blob(new_msg,sizeof(gsmtap_hdr)+BURST_SIZE);
             pmt::pmt_t msg_out = pmt::cons(pmt::PMT_NIL, msg_binary_blob);