diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6e0fbb7b..bc0fa191 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -121,6 +121,14 @@ option(LWS_AVOID_SIGPIPE_IGN "Android 7+ seems to need this" OFF)
 option(LWS_WITH_STATS "Keep statistics of lws internal operations" OFF)
 option(LWS_WITH_SOCKS5 "Allow use of SOCKS5 proxy on client connections" OFF)
 
+macro(confirm_command CMD NOCMD)
+	find_program (HAVE_CMD_${CMD} ${CMD} )
+	if (NOT HAVE_CMD_${CMD})
+		message(FATAL_ERROR "Missing command ${CMD} required for build: ${NOCMD}" )
+	endif()
+endmacro()
+
+
 if (LWS_WITH_LWSWS)
  message(STATUS "LWS_WITH_LWSWS --> Enabling LWS_WITH_PLUGINS and LWS_WITH_LIBUV")
  set(LWS_WITH_PLUGINS 1)
@@ -169,6 +177,10 @@ if (LWS_WITH_ESP8266)
 endif()
 
 if (LWS_WITH_ESP32)
+
+	confirm_command(xxd "usually found in vim package")
+	confirm_command(genromfs "install genromfs package")
+
  set(LWS_WITH_SHARED OFF)
  set(LWS_USE_MBEDTLS ON)
   # set(LWS_WITHOUT_CLIENT ON)