diff --git a/src/wasm/wrt/ngx_wrt_wasmer.c b/src/wasm/wrt/ngx_wrt_wasmer.c
index 05aed26b3..497e4cdfe 100644
--- a/src/wasm/wrt/ngx_wrt_wasmer.c
+++ b/src/wasm/wrt/ngx_wrt_wasmer.c
@@ -77,7 +77,7 @@ ngx_wasmer_init_conf(ngx_wavm_conf_t *conf, ngx_log_t *log)
     ngx_wasm_assert(conf->backtraces != NGX_CONF_UNSET);
 
     if (conf->backtraces) {
-        setenv("RUST_BACKTRACE", "FULL", 1);
+        setenv("RUST_BACKTRACE", "full", 1);
 
     } else {
         setenv("RUST_BACKTRACE", "0", 0);
diff --git a/src/wasm/wrt/ngx_wrt_wasmtime.c b/src/wasm/wrt/ngx_wrt_wasmtime.c
index c4e0db600..e62c0ffd9 100644
--- a/src/wasm/wrt/ngx_wrt_wasmtime.c
+++ b/src/wasm/wrt/ngx_wrt_wasmtime.c
@@ -135,7 +135,7 @@ ngx_wasmtime_init_conf(ngx_wavm_conf_t *conf, ngx_log_t *log)
 
     if (conf->backtraces) {
         setenv("WASMTIME_BACKTRACE_DETAILS", "1", 1);
-        setenv("RUST_BACKTRACE", "FULL", 1);
+        setenv("RUST_BACKTRACE", "full", 1);
 
     } else {
         setenv("WASMTIME_BACKTRACE_DETAILS", "0", 0);