Long CX II operations — listing a folder with many entries, downloading a
file of any size — failed with a reported `Busy`.
readPacket checksummed `transferred`, the byte count libusb returned, rather
than `completeLength`, the length the packet declares. The calculator can
hand back more bytes than the packet occupies (a 64-byte packet arriving as
65 was what showed up in tracing), and the stray byte failed the checksum.
The packet was dropped and so never acked, the calculator retransmitted the
same sequence number indefinitely, and the receive loop gave up after 40
reads. `transferred` was also wrong after the multi-chunk continuation loop,
where it holds only the final chunk's size — the reason large stream
transfers were unreliable.
Also add NNSE retransmission to packet_send_cx2. A lost packet or lost ack
was previously fatal, since the packet was written exactly once. Retries now
carry the "not the first try" bit (reqAck bit 3) that TI's own stack sets,
keeping the same seqno so the calculator can drop a duplicate. This path did
not trigger in testing — every packet acked on the first attempt once the
checksum was fixed — so its timeouts are deliberately generous to avoid
retransmitting during slow flash writes.
While here, zero `misc` and `unknown` instead of sending malloc garbage
inside a checksummed header, and handle allocation failure.
Verified against CX II firmware (0451:e022): `ls /` returns all 51 entries
across 8 runs, a 193 KB download is byte-identical across two runs, and
mkdir/rmdir round-trips.
Note the error was never actually Busy. The libnspire crate (0.2.3) matches
its positive NSPIRE_ERR_* constants against libnspire's negative return
codes, so every error falls through to the libusb table and is mislabelled;
-NSPIRE_ERR_INVALPKT and LIBUSB_ERROR_BUSY are both -6. That mismapping is
upstream in the crate and is not addressed here.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Tauri 1.0.0-beta.8 links webkit2gtk-4.0, unavailable on Ubuntu 26.04.
Verified: builds and links libwebkit2gtk-4.1.so.0, libsoup-3.0.so.0,
libjavascriptcoregtk-4.1.so.0 with no webkit-4.0 or libssl.1.1 refs.
Workspace moved from yarn to npm; yarn.lock invalidated by this port.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
