Now extend Goplat's earlier idea:
copy /phoenix/install/TI-Nspire.tnc /phx/documents/examples/OS.tns
and transfer through USB

or something similar

PK is part of the zip file header so that is expected with a zip.

Oh, this looks cool.  Great job, critor, Goplat, and bsl.

I just checked out the type command in the current boot2 - it reads 1023 bytes at at a time, and prints using printf, so if the file has any 00 bytes it'll lose data. ! Stupid Datalight programmers. They didn't even do printf("%s", buffer), they did printf(buffer), so if there are %s's in the file it'll likely crash (this is not exploitable, unfortunately).

I may be leading you astray
try +++ at the hyperterminal prompt
you might start xmodem transfer.

I found a post with a list of commands (don't know if it is complete) of the Datalight shell from Boot2 1.4:

?                    - Display help
APPEND               - Appends data from the console to a file
CD                   - Change the current directory
Check                - Check a Reliance disk
COMPARE              - Compare the contents of two files
CompTest             - Run the Reliance for Nucleus compatibility test
COPY                 - Copy a file
CREATE               - Create a file
DCLTEST              - Execute the DCL unit tests
DEL                  - Delete a file
DIR                  - Display a directory listing
EXIT                 - Exit the shell
FlashFXCheck         - Check the spare unit on disk
FlashFXDiskInfo      - Display FlashFX information
FlashFXDump          - Dump a FlashFX disk image
FlashFXImage         - Read or write a FlashFX disk
FlashFXRemount       - Remount a disk
FlashFXStressMT      - Execute the Multi-threaded VBF unit test
FlashFXTestFMSL      - Execute the FMSL unit test
FlashFXTestVBF       - Execute the VBF unit test
Format               - Format a disk
FSIOTEST             - Execute the File System I/O tests
GetTrans             - Display the transaction mode
HELP                 - Display help
MD                   - Make a directory
RD                   - Remove a directory
REN                  - Rename a file
SetTrans             - Set the transaction mode
Show                 - Display information of a Reliance disk
Test                 - Run the Reliance test suite
TIME                 - Display the current time
TYPE                 - Display the contents of a file on the console
WRITE                - Write to a file using console input

I've striked what didn't work for me.
In bold, what worked.
The rest is untested.

Anything interesting? Anything dangerous?

I don't think it's that important, but I've missed something at the end of my oldest bootlog:

Launching system...

Datalight Command Shell for Nucleus

A:�‘¤œ‘H>01 00:00:50.000 0 | Initializing xmlrpc library
As more recent CAS+ are only listing through USB and Computer Link modified code:
/
/phx/
/phx/documents/
/phx/tmp/

I'm wondering if this is related to those A: and C: drives.

Maybe this is the A: drive content, and "/phx/documents" and "/phx/tmp" folders are only links to the "/phoenix/documents" and "/phoenix/tmp" folders from the C: drive.

Maybe, those uninteresting folders are in A:.
If we could add the "C:" prefix in this code, maybe...

If possible, any idea about the Computer Link syntax for that?
"c:/..." ?
"/c/..." ?
"/c:/..." ?