diff --git a/internal/http/download_test.go b/internal/http/download_test.go
index 4e50adb6df06..ccd259ccd4c2 100644
--- a/internal/http/download_test.go
+++ b/internal/http/download_test.go
@@ -15,7 +15,6 @@ import (
 	"strings"
 	"sync/atomic"
 	"testing"
-	"time"
 
 	"github.com/k0sproject/k0s/internal/testutil"
 
@@ -79,18 +78,21 @@ func TestDownload_ExcessContentLength(t *testing.T) {
 func TestDownload_CancelDownload(t *testing.T) {
 	ctx, cancel := context.WithCancelCause(t.Context())
 
+	requestDone := make(chan struct{})
 	baseURL := startFakeDownloadServer(t, false, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		for {
-			if _, err := w.Write([]byte(t.Name())); !assert.NoError(t, err) {
-				return
-			}
-
-			select {
-			case <-r.Context().Done():
-				return
-			case <-time.After(time.Microsecond):
-			}
+		defer close(requestDone)
+		if _, err := w.Write([]byte(t.Name())); !assert.NoError(t, err) {
+			return
 		}
+
+		// Need to flush here, otherwise the internal response buffering will
+		// prevent the client from receiving the data.
+		w.(http.Flusher).Flush()
+
+		// Wait for the client to cancel the in-flight request.
+		ctx := r.Context()
+		<-ctx.Done()
+		assert.Same(t, context.Canceled, context.Cause(ctx), "HTTP request context wasn't canceled while writing response")
 	}))
 
 	err := internalhttp.Download(ctx, baseURL, internalio.WriterFunc(func(p []byte) (int, error) {
@@ -100,6 +102,10 @@ func TestDownload_CancelDownload(t *testing.T) {
 
 	assert.ErrorContains(t, err, "while downloading: ")
 	assert.ErrorIs(t, err, assert.AnError)
+
+	// Make sure the server's HTTP handler has finished
+	// so all the assertions have been made.
+	<-requestDone
 }
 
 func TestDownload_RedirectLoop(t *testing.T) {