diff --git a/nmigen/vendor/tinyfpga_b.py b/nmigen/vendor/tinyfpga_b.py
index ecb0c58..6960b84 100644
--- a/nmigen/vendor/tinyfpga_b.py
+++ b/nmigen/vendor/tinyfpga_b.py
@@ -12,9 +12,9 @@ class TinyFPGABPlatform(TinyProgrammerMixin, LatticeICE40Platform):
         ("clk16", 16e6),
     ]
     resources = [
-        Resource("clk16", 0, Pins("B2", dir="i"), extras=["IO_STANDARD=LVCMOS33"]),
+        Resource("clk16", 0, Pins("B2", dir="i"), extras=["IO_STANDARD=SB_LVCMOS33"]),
 
-        Resource("user_led", 0, Pins("B3", dir="o"), extras=["IO_STANDARD=LVCMOS33"]),
+        Resource("user_led", 0, Pins("B3", dir="o"), extras=["IO_STANDARD=SB_LVCMOS33"]),
 
         Resource("usb", 0,
             Subsignal("d_p", Pins("B4", dir="io")),