diff --git a/common/boot_command/boot_command_ast.go b/common/boot_command/boot_command_ast.go
index 87457a22c..f9605a67b 100644
--- a/common/boot_command/boot_command_ast.go
+++ b/common/boot_command/boot_command_ast.go
@@ -15,8 +15,6 @@ TODO:
 	* comments
 	* lower-case specials
 	* check that `<del>` works on parallels. It's different now.
-	* take `Finalize` out of the Driver interface. let builders that need it
-		* use it. also rename to `Flush`.
 */
 
 // KeysAction represents what we want to do with a key press.
diff --git a/common/boot_command/pc_at_driver.go b/common/boot_command/pc_at_driver.go
index ca87c1926..b89dcc081 100644
--- a/common/boot_command/pc_at_driver.go
+++ b/common/boot_command/pc_at_driver.go
@@ -25,6 +25,9 @@ type pcATDriver struct {
 	scancodeChunkSize int
 }
 
+// NewPCATDriver creates a new boot command driver for VMs that expect PC-AT
+// keyboard codes. `send` should send its argument to the VM. `chunkSize` should
+// be the maximum number of keyboard codes to send to `send` at one time.
 func NewPCATDriver(send SendCodeFunc, chunkSize int) *pcATDriver {
 	// We delay (default 100ms) between each input event to allow for CPU or
 	// network latency. See PackerKeyEnv for tuning.