diff --git a/watchdog/justfile b/watchdog/justfile
index 884ba3d..d3a6998 100644
--- a/watchdog/justfile
+++ b/watchdog/justfile
@@ -31,5 +31,5 @@ doctor:
         exit 1; \
     }
     @lua -e "package.cpath = '.deps/lua/?.so;' .. package.cpath; require('lcurl'); print('doctor: lcurl ok')"
-    @lua -e "package.path = './?.lua;./?/init.lua;' .. package.path; local m=require('watchdog.machine_cartesi').new(); local inst,err=m:load('examples/canonical-app/out/canonical-machine-image'); if not inst then error('doctor: machine_cartesi cannot load devnet image: '..tostring(err)) end; print('doctor: machine_cartesi load ok')"
+    @LUA_CPATH_5_4="/usr/lib/lua/5.4/?.so;/usr/lib/lua/5.4/?/init.so;${LUA_CPATH_5_4:-;}" LUA_PATH_5_4="/usr/share/lua/5.4/?.lua;/usr/share/lua/5.4/?/init.so;${LUA_PATH_5_4:-;}" lua -e "package.path = './?.lua;./?/init.lua;' .. package.path; local m=require('watchdog.machine_cartesi').new(); local inst,err=m:load('examples/canonical-app/out/canonical-machine-image'); if not inst then error('doctor: machine_cartesi cannot load devnet image: '..tostring(err)) end; print('doctor: machine_cartesi load ok')"
     @echo "doctor: watchdog toolchain ok"
diff --git a/watchdog/sequencer-watchdog b/watchdog/sequencer-watchdog
index a92f099..744661f 100755
--- a/watchdog/sequencer-watchdog
+++ b/watchdog/sequencer-watchdog
@@ -11,6 +11,16 @@ fi
 lua_root="${CARTESI_WATCHDOG_LUA_ROOT:-/opt/watchdog/lua}"
 lua_bin="${CARTESI_WATCHDOG_LUA_BIN:-lua5.4}"
 
+# Prefer deb-installed cartesi bindings under /usr/lib over stale /usr/local
+# copies left by an older manual install (same ordering as the cartesi-machine
+# wrapper shipped in machine-emulator_*.deb).
+_cartesi_lua_cpath="/usr/lib/lua/5.4/?.so;/usr/lib/lua/5.4/?/init.so"
+_cartesi_lua_path="/usr/share/lua/5.4/?.lua;/usr/share/lua/5.4/?/init.so"
+export LUA_CPATH="${_cartesi_lua_cpath};${LUA_CPATH:-;}"
+export LUA_PATH="${_cartesi_lua_path};${LUA_PATH:-;}"
+export LUA_CPATH_5_4="${_cartesi_lua_cpath};${LUA_CPATH_5_4:-;}"
+export LUA_PATH_5_4="${_cartesi_lua_path};${LUA_PATH_5_4:-;}"
+
 cd "${lua_root}"
 
 if [[ "$#" -gt 0 && ( "$1" == "init" || "$1" == "tick" ) ]]; then