work around bladeRF FPGA loading and bias-tee problems

shell.nix

@@ -16,6 +16,22 @@ let
     url = "https://www.nuand.com/fpga/v0.11.0/hostedxA4.rbf";
     sha256 = "c172e35c4a92cf1e0ca3b37347a84d8376b275ece16cb9c5142b72b82b16fe8e";
   };
+  bladeRF-flash = pkgs.writeShellScriptBin "bladeRF-flash"
+    # Using the bladeRF bias-tee is royally annoying. Opening the bladeRF turns it off,
+    # and the API for turning it back on isn't exposed in SoapySDR. Using the configuration
+    # file works, but breaks FPGA loading since bladeRF-cli then attempts to turn on the
+    # bias-tee before loading the FPGA. Using the configuration file to load the FPGA
+    # works the first time and then crashes until the bladeRF is unplugged and plugged back in.
+    # To work around these assorted bugs, we flash the bladeRF from an empty directory where
+    # bladeRF-cli won't find the configuration file, and let it boot the FPGA from its flash, 
+    # which seems less buggy/cumbersome than the other options.
+    ''
+    TMPDIR=`mktemp -d`
+    pushd $TMPDIR
+    ${pkgs.libbladeRF}/bin/bladeRF-cli -L ${bitstream}
+    popd
+    rmdir $TMPDIR
+    '';
   sipyco = pkgs.python3Packages.buildPythonPackage rec {
     name = "sipyco";
     version = "1.1";
@@ -33,13 +49,11 @@ in
     buildInputs = [
       (pkgs.python3.withPackages(ps: [ps.soapysdr-with-plugins ps.scipy ps.pyserial ps.quamash ps.pyqt5 pyqtgraph-qt5 sipyco]))
       pkgs.libbladeRF pkgs.gqrx
+      bladeRF-flash
     ];
     dontWrapQtApps = true;
     postFixup = ''
        wrapQtApp "$out/bin/python"
     '';
-    shellHook = ''
-      ${pkgs.libbladeRF}/bin/bladeRF-cli -l ${bitstream}
-    '';
     QT_QPA_PLATFORM = "wayland";
   }