diff --git a/misoclib/tools/litescope/host/driver/etherbone.py b/misoclib/tools/litescope/host/driver/etherbone.py
index 0f3efd158..44959887f 100644
--- a/misoclib/tools/litescope/host/driver/etherbone.py
+++ b/misoclib/tools/litescope/host/driver/etherbone.py
@@ -11,7 +11,8 @@ class LiteScopeEtherboneDriver:
 
 		self.tx_sock = None
 		self.rx_sock = None
-		self.regs = build_map(addrmap, busword, self.read, self.write)
+		if addrmap is not None:
+			self.regs = build_map(addrmap, busword, self.read, self.write)
 
 	def open(self):
 		self.tx_sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
diff --git a/misoclib/tools/litescope/host/driver/uart.py b/misoclib/tools/litescope/host/driver/uart.py
index 4771c989b..da3cd3635 100644
--- a/misoclib/tools/litescope/host/driver/uart.py
+++ b/misoclib/tools/litescope/host/driver/uart.py
@@ -15,7 +15,8 @@ class LiteScopeUARTDriver:
 		self.baudrate = str(baudrate)
 		self.debug = debug
 		self.uart = serial.Serial(port, baudrate, timeout=0.25)
-		self.regs = build_map(addrmap, busword, self.read, self.write)
+		if addrmap is not None:
+			self.regs = build_map(addrmap, busword, self.read, self.write)
 
 	def open(self):
 		self.uart.flushOutput()