diff --git a/cue-ios/CueIOS/Assets.xcassets/AppIcon.appiconset/appicon-1024.png b/cue-ios/CueIOS/Assets.xcassets/AppIcon.appiconset/appicon-1024.png
index 5933ffe..7c1cc0b 100644
Binary files a/cue-ios/CueIOS/Assets.xcassets/AppIcon.appiconset/appicon-1024.png and b/cue-ios/CueIOS/Assets.xcassets/AppIcon.appiconset/appicon-1024.png differ
diff --git a/main/eis.c b/main/eis.c
index 8ddf1e0..7854090 100644
--- a/main/eis.c
+++ b/main/eis.c
@@ -270,6 +270,7 @@ static void configure_freq(float freq_hz)
 
 static int32_t sign_extend_18(uint32_t v)
 {
+    v &= 0x3FFFF;  /* DFT register is 18-bit; mask off ECC/status junk in upper bits */
     return (v & (1UL << 17)) ? (int32_t)(v | 0xFFFC0000UL) : (int32_t)v;
 }
 
@@ -297,31 +298,26 @@ static void dft_measure_pair(
     AD5940_AFECtrlS(AFECTRL_WG | AFECTRL_ADCPWR, bTRUE);
     settle(freq_hz, 2.0f, 100);
 
-    AD5940_ClrMCUIntFlag();
+    AD5940_INTCClrFlag(AFEINTSRC_DFTRDY);
     AD5940_AFECtrlS(AFECTRL_ADCCNV | AFECTRL_DFT, bTRUE);
-    while (!AD5940_GetMCUIntFlag())
+    while (!AD5940_INTCTestFlag(AFEINTC_1, AFEINTSRC_DFTRDY))
         vTaskDelay(1);
     AD5940_AFECtrlS(AFECTRL_ADCCNV | AFECTRL_DFT, bFALSE);
-    AD5940_INTCClrFlag(AFEINTSRC_DFTRDY);
 
     out1->Real  = sign_extend_18(AD5940_ReadAfeResult(AFERESULT_DFTREAL));
     out1->Image = sign_extend_18(AD5940_ReadAfeResult(AFERESULT_DFTIMAGE));
     out1->Image = -out1->Image;
 
-    /* switch ADC mux, flush stale pipeline, settle one period */
+    /* switch ADC mux, settle one period */
     AD5940_ADCMuxCfgS(mux2_p, mux2_n);
-    AD5940_ReadAfeResult(AFERESULT_DFTREAL);
-    AD5940_ReadAfeResult(AFERESULT_DFTIMAGE);
-    AD5940_INTCClrFlag(AFEINTSRC_DFTRDY);
     settle(freq_hz, 1.0f, 50);
 
-    AD5940_ClrMCUIntFlag();
+    AD5940_INTCClrFlag(AFEINTSRC_DFTRDY);
     AD5940_AFECtrlS(AFECTRL_ADCCNV | AFECTRL_DFT, bTRUE);
-    while (!AD5940_GetMCUIntFlag())
+    while (!AD5940_INTCTestFlag(AFEINTC_1, AFEINTSRC_DFTRDY))
         vTaskDelay(1);
     AD5940_AFECtrlS(AFECTRL_ADCCNV | AFECTRL_DFT |
                     AFECTRL_WG | AFECTRL_ADCPWR, bFALSE);
-    AD5940_INTCClrFlag(AFEINTSRC_DFTRDY);
 
     out2->Real  = sign_extend_18(AD5940_ReadAfeResult(AFERESULT_DFTREAL));
     out2->Image = sign_extend_18(AD5940_ReadAfeResult(AFERESULT_DFTIMAGE));