diff --git a/gateware/litex_main.py b/gateware/litex_main.py
index 8a11a18..42c5d43 100755
--- a/gateware/litex_main.py
+++ b/gateware/litex_main.py
@@ -27,7 +27,7 @@ from litedram.phy import GENSDRPHY, HalfRateGENSDRPHY
 
 from liteeth.phy.ecp5rgmii import LiteEthPHYRGMII
 
-from sampler import Sampler
+from sampler import SamplerController, Sampler
 from litex.soc.integration.soc import SoCRegion
 
 from test import run_test, TestResult, skip_suite
@@ -143,11 +143,11 @@ class BaseSoC(SoCCore):
             if with_video_framebuffer:
                 self.add_video_framebuffer(phy=self.videophy, timings="800x600@60Hz", clock_domain="hdmi")
 
-        self.submodules.sampler = Sampler(platform.request("adc"), self.crg.cd_sample_clock.clk)
-        sampler_region = SoCRegion(origin=None, size=0x1000, cached=False)
-        #self.add_wb_slave(0x9000_0000, self.sampler.bus, 0x1000)
-        ## TODO better way to do this?
-        #self.bus.add_slave(name="sampler", slave=self.sampler.bus, region=sampler_region)
+        #samplers = [Sampler(platform.request("adc", i)) for i in range(3)]
+        #self.submodules.sampler_controller = SamplerController(samplers, buffer_len=2048 * 10)
+        ### TODO better way to do this?
+        #sampler_region = SoCRegion(origin=None, size=0x4000, cached=False)
+        #self.bus.add_slave(name="sampler", slave=self.sampler_controller.bus, region=sampler_region)
 
 # Build --------------------------------------------------------------------------------------------
 
@@ -200,8 +200,9 @@ def main():
 
         print(f"{passed}/{passed + failed} passed ({skipped} skipped)")
 
-        # TODO maybe don't do this?
-        return
+        if failed > 0 or not args.build:
+            # Don't also build after this
+            return
 
     # Build firmware
     import subprocess as sp
diff --git a/gateware/platforms/sonar.py b/gateware/platforms/sonar.py
index 0232783..135011d 100644
--- a/gateware/platforms/sonar.py
+++ b/gateware/platforms/sonar.py
@@ -175,9 +175,7 @@ _io_v7_2 = copy.deepcopy(_io_v7_0)
 
 for i, x in enumerate(_io_v7_2):
     if x[:2] == ("user_led_n", 0):
-        # TODO fix in HW
-        #_io_v7_2[i] = ("user_led_n", 0, Pins("L2"), IOStandard("LVCMOS33"))
-        _io_v7_2[i] = ("user_led_n", 0, Pins("J19"), IOStandard("LVCMOS33"))
+        _io_v7_2[i] = ("user_led_n", 0, Pins("L2"), IOStandard("LVCMOS33"))
         break
 
 # optional, alternative uart location
diff --git a/gateware/sampler/circular_buffer.py b/gateware/sampler/circular_buffer.py
index 513e07b..062a446 100644
--- a/gateware/sampler/circular_buffer.py
+++ b/gateware/sampler/circular_buffer.py
@@ -34,14 +34,23 @@ class CircularBuffer(Module):
         rd_ptr = Signal(ptr_width)
         empty = Signal(reset=1) # Extra signal to distinguish between full and empty condition
 
+        # TODO this shouldn't be needed. Bug in migen IMO, I don't use this signal
+        dat_r = Signal(width)
+
         # Hook write input signals to memory
         wr_port = storage.get_port(write_capable=True)
+        # TODO hacky bullshit because migen is broken or I'm using it wrong
+        if not hasattr(wr_port.clock, "cd"):
+            wr_port.clock.cd = "sys"
+
         # Always ready to write data into memory, so hook these signals straight in
         self.comb += [
             wr_port.adr.eq(wr_ptr),
             wr_port.dat_w.eq(self.wr_data),
             wr_port.we.eq(self.wr_valid),
             self.wr_ready.eq(1),            # We are always ready to write data in
+
+            dat_r.eq(wr_port.dat_r)
         ]
 
         # Advance write (and potentially read)
@@ -66,6 +75,10 @@ class CircularBuffer(Module):
 
         # TODO should I actually set async_read?
         rd_port = storage.get_port(async_read=True)
+        # TODO hacky bullshit because migen is broken or I'm using it wrong
+        if not hasattr(rd_port.clock, "cd"):
+            rd_port.clock.cd = "sys"
+
         # Set read addr so 0 starts at rd_ptr and wraps around, and connect read data up
         self.comb += [
             If(self.rd_addr + rd_ptr < depth,
diff --git a/gateware/sampler/sampler.py b/gateware/sampler/sampler.py
index ff16d26..5e60b9b 100644
--- a/gateware/sampler/sampler.py
+++ b/gateware/sampler/sampler.py
@@ -3,14 +3,9 @@ from migen.genlib.cdc import PulseSynchronizer
 
 
 class Sampler(Module):
-    def __init__(self, adc_pins: Record, sampler_clock: Signal):
-        # self.clock_domains.foo = ClockDomain() is how to add a new clock domain, accessible at self.foo
-        # Connect sampler clock domain
-        self.clock_domains.sample_clock = ClockDomain("sample_clock")
-        self.comb += self.sample_clock.clk.eq(sampler_clock)
-
+    def __init__(self, adc_pins: Record):
         # Hook up ADC REFCLK to sample_clock
-        self.comb += adc_pins.refclk.eq(sampler_clock)
+        self.comb += adc_pins.refclk.eq(ClockDomain("sample_clock").clk)
 
         # We can synchronize to the sampler clock, whenever it goes high we can
         # strobe a single valid signal
@@ -21,10 +16,10 @@ class Sampler(Module):
         self.data = Signal(10)
 
         self.comb += [
-            synchronizer.i.eq(self.sample_clock.clk),
+            synchronizer.i.eq(ClockDomain("sample_clock").clk),
             self.valid.eq(synchronizer.o),
-            self.data.eq(adc_pins.data),
         ]
+        self.sync += self.data.eq(adc_pins.data)
 
         # Set config pins to constant values
         self.comb += adc_pins.oen_b.eq(0)       # Data pins enable