[kfox]

Link.delete() in tools/bench/trlink.py sent its drive byte and path whatever the reply to its token was. While any IO handler other than the menu's is current, the full firmware answers a file command with FailToken and Busy! and reads nothing more (SerUSBIO.ino, the CurrentIOHandler != IOH_TeensyROM refusal), so the path bytes that followed were run as one-letter serial commands. Pushing /c128test/t80b.prg to a board with REU+USB Mouse/Disk as Special IO reset its EEPROM to defaults (the e in "test"), cleared the debug log (c) and started a timing command (t). post() deletes first, so every push.py to a busy board did this, and the Busy! on the post token that followed hid it.

delete() now checks its token reply with ack(), as post(), listdir() and launch() already did. A refused delete sends nothing further and fails as delete <path>: FAIL - Busy!. The delete's second reply is still not checked, because the firmware answers "File not found" for a new file, which is the usual case for a push.

The other bench tools were checked for the same pattern: spans.py already checks for the ack before each payload, and the rest send each command in one write or send nothing after a reply.

Verification

• A new test, test_a_busy_board_is_sent_no_path_to_run_as_commands, pushes to a fake board that refuses file commands while busy and records every byte the firmware would run as a command. Before the fix it failed with b'\x01/c128test/t80b.prg\x00' != b''; after, it passes. Putting the old self.rd(2) back in place of the ack check makes it fail again.
• python3 -m unittest discover -s tools/bench: 86 tests, OK. npm test: pass.
• The EEPROM reset was seen on a TR+ in an NTSC C128 (the settings page showed Special IO back to None after a refused push). The fix itself is host tested only; no firmware changes.

Reviewed at low (23 changed code lines), no findings.

[SensoriumEmbedded]

Thank you for catching this one, an EEPROM reset from a file push is a nasty one to track down!

I reviewed this merged onto current main (ac24701). Nothing to change, merging now.

Thank you!