diff --git a/src/cli/parse-flags.ts b/src/cli/parse-flags.ts
index 9e1a2a5c937..d4a14c07546 100644
--- a/src/cli/parse-flags.ts
+++ b/src/cli/parse-flags.ts
@@ -1,4 +1,4 @@
-import { CompilerSystem, LogLevel, LOG_LEVELS, TaskCommand } from '../declarations';
+import { LogLevel, LOG_LEVELS, TaskCommand } from '../declarations';
 import { dashToPascalCase, toDashCase } from '@utils';
 import {
   BOOLEAN_CLI_ARGS,
@@ -20,11 +20,9 @@ import {
  * Parse command line arguments into a structured `ConfigFlags` object
  *
  * @param args an array of CLI flags
- * @param _sys an optional compiler system
  * @returns a structured ConfigFlags object
  */
-export const parseFlags = (args: string[], _sys?: CompilerSystem): ConfigFlags => {
-  // TODO(STENCIL-509): remove the _sys parameter here ^^ (for v3)
+export const parseFlags = (args: string[]): ConfigFlags => {
   const flags: ConfigFlags = createConfigFlags();
 
   // cmd line has more priority over npm scripts cmd
diff --git a/src/cli/public.ts b/src/cli/public.ts
index 57c7526745d..dc08b626dea 100644
--- a/src/cli/public.ts
+++ b/src/cli/public.ts
@@ -1,4 +1,4 @@
-import type { CliInitOptions, CompilerSystem, Config, Logger, TaskCommand } from '@stencil/core/internal';
+import type { CliInitOptions, Config, Logger, TaskCommand } from '@stencil/core/internal';
 import type { ConfigFlags } from './config-flags';
 
 /**
@@ -15,7 +15,6 @@ export declare function run(init: CliInitOptions): Promise<void>;
  */
 export declare function runTask(coreCompiler: any, config: Config, task: TaskCommand): Promise<void>;
 
-// TODO(STENCIL-509): remove the _sys parameter here (for v3)
-export declare function parseFlags(args: string[], _sys?: CompilerSystem): ConfigFlags;
+export declare function parseFlags(args: string[]): ConfigFlags;
 
-export { CompilerSystem, Config, ConfigFlags, Logger, TaskCommand };
+export { Config, ConfigFlags, Logger, TaskCommand };