diff --git a/debian_specs/passenger/passenger_free_ruby.c b/debian_specs/passenger/passenger_free_ruby.c
index aba70df..fd20a9a 100644
--- a/debian_specs/passenger/passenger_free_ruby.c
+++ b/debian_specs/passenger/passenger_free_ruby.c
@@ -15,22 +15,15 @@
 int
 main(int argc, const char *argv[]) {
 	try_exec("ruby", argc, argv);
-	try_exec("/usr/bin/ruby3.4", argc, argv);
-	try_exec("/usr/bin/ruby3.3", argc, argv);
-	try_exec("/usr/bin/ruby3.2", argc, argv);
-	try_exec("/usr/bin/ruby3.1", argc, argv);
-	try_exec("/usr/bin/ruby3.0", argc, argv);
-	try_exec("/usr/bin/ruby2.7", argc, argv);
-	try_exec("/usr/bin/ruby2.6", argc, argv);
-	try_exec("/usr/bin/ruby2.5", argc, argv);
-	try_exec("/usr/bin/ruby2.4", argc, argv);
-	try_exec("/usr/bin/ruby2.3", argc, argv);
-	try_exec("/usr/bin/ruby2.2", argc, argv);
-	try_exec("/usr/bin/ruby2.1", argc, argv);
-	try_exec("/usr/bin/ruby2.0", argc, argv);
+	char* exe = "/usr/bin/rubyX.XX";
+	for(int m = 4; m > 0; m--) {
+		for(int n = 10; n > -1; n--) {
+			snprintf(exe, 18, "/usr/bin/ruby%i.%i", m, n);
+			try_exec(exe, argc, argv);
+		}
+	}
 	try_exec("/usr/bin/ruby1.9.1", argc, argv);
-	try_exec("/usr/bin/ruby1.8", argc, argv);
 
-	fprintf(stderr, "passenger_free_ruby: cannot find suitable Ruby interpreter\n");
+	fprintf(stderr, PROGRAM_NAME ": cannot find suitable Ruby interpreter\n");
 	return 1;
 }
diff --git a/debian_specs/passenger/passenger_system_ruby.c.erb b/debian_specs/passenger/passenger_system_ruby.c.erb
index 26c7133..b8f70d2 100644
--- a/debian_specs/passenger/passenger_system_ruby.c.erb
+++ b/debian_specs/passenger/passenger_system_ruby.c.erb
@@ -1,9 +1,7 @@
 <%
 require File.dirname(File.absolute_path(__FILE__)) + '/helpers'
 all_ruby_versions_to_try = distro_ruby_versions.reverse +
-  ['3.4', '3.3', '3.2', '3.1', '3.0',
-   '2.7', '2.6', '2.5', '2.4', '2.3',
-   '2.2', '2.1', '2.0', '1.9.1', '1.8']
+  (1..4).to_a.product((0..10).to_a).map{|x,y|"#{x}.#{y}"}.reverse.push('1.9.1')
 all_ruby_versions_to_try.uniq!
 -%>
 /*
@@ -27,8 +25,27 @@ all_ruby_versions_to_try.uniq!
 #define PROGRAM_NAME "passenger_system_ruby"
 #include "passenger_ruby_utils.c"
 
+static void
+try_unset(const char* s){
+	if (0 != unsetenv(s)) {
+		int e = errno;
+		fprintf(stderr, PROGRAM_NAME ": cannot unset '%s': %s\n",s, strerror(e));
+		exit(1);
+	}
+}
+
+static void
+reset_env() {
+	try_unset("GEM_HOME");
+	try_unset("GEM_PATH");
+	try_unset("RUBYOPT");
+	try_unset("RUBYPATH");
+	try_unset("RUBYLIB");
+}
+
 int
 main(int argc, const char *argv[]) {
+	reset_env();
 	<% for ruby_version in all_ruby_versions_to_try.reverse -%>
 		try_exec("/usr/bin/ruby<%= ruby_version %>", argc, argv);
 	<% end -%>