diff --git a/common/util.cc b/common/util.cc
index ee1080cbdf..a527adcbef 100644
--- a/common/util.cc
+++ b/common/util.cc
@@ -189,7 +189,7 @@ bool create_directories(const std::string& dir, mode_t mode) {
   return createDirectory(dir, mode);
 }
 
-std::string getenv(const char* key, const char* default_val) {
+std::string getenv(const char* key, std::string default_val) {
   const char* val = ::getenv(key);
   return val ? val : default_val;
 }
diff --git a/common/util.h b/common/util.h
index c80dc234f2..34721700e7 100644
--- a/common/util.h
+++ b/common/util.h
@@ -70,7 +70,7 @@ std::string string_format(const std::string& format, Args... args) {
   return std::string(buf.get(), buf.get() + size - 1);
 }
 
-std::string getenv(const char* key, const char* default_val = "");
+std::string getenv(const char* key, std::string default_val = "");
 int getenv(const char* key, int default_val);
 float getenv(const char* key, float default_val);
 
diff --git a/system/hardware/hw.h b/system/hardware/hw.h
index 5599e79186..3b0583a10b 100644
--- a/system/hardware/hw.h
+++ b/system/hardware/hw.h
@@ -19,7 +19,7 @@ inline std::string log_root() {
   return Hardware::PC() ? util::getenv("HOME") + "/.comma/media/0/realdata" : "/data/media/0/realdata";
 }
 inline std::string params() {
-  return Hardware::PC() ? util::getenv("HOME") + "/.comma/params" : "/data/params";
+  return Hardware::PC() ? util::getenv("PARAMS_ROOT", util::getenv("HOME") + "/.comma/params") : "/data/params";
 }
 inline std::string rsa_file() {
   return Hardware::PC() ? util::getenv("HOME") + "/.comma/persist/comma/id_rsa" : "/persist/comma/id_rsa";