USB IR Toy firmware updating on Linux

[Matthew W. <mw...@wt...>]

i have been using the USB IR Toy from Dangerous Prototypes for years 
with my Raspberry Pi systems to control all of my entertainment devices 
(TV, Sound Bar, DVR, Apple TV, etc).

back when i was experimenting a lot, i used to have to re-update the 
firmware more frequently than i expected, but the most recent load had 
lasted me over 2 years; until this week.

i always used the fw_update(.exe) command under Windows because that was 
the only examples i could find online.  works fine.  i even customised 
my firmware binary files to include custom a "Serial Number" for each of 
my devices, so i could differentiate them in udev rules on the Pi.

now, this week, i was experimenting again and messed up the Toy and must 
now re-update the firmware again to get it to function.  i wonder about 
the possibility of doing so from the Pi to avoid dragging the old 
Windows laptop out again, and dragging the Toy out from the 
entertainment center to work on the Toy (jumping PGC/PGD).  the Toy 
"firmware update" page mentions being able to use a serial connection to 
activate the bootloader.  Linux has the "setserial" command that ought 
to function like the "terminal" command on Windows.

has anyone successfully done a firmware update using UNIX/Linux alone?

even assuming i can put the Toy in bootloader mode, does anyone know 
what to use under Linux to replace the Windows fw_update 
command/executable functionality?  just use "cat" to dump the contents 
of the binary file into the serial stream after sending "$" to enter 
bootloader mode?

Pi:  Raspberry Pi 4 Model B Rev 1.1 with 2 gig of memory
OS:  Debian GNU/Linux 12 (bookworm)
Toy: http://dangerousprototypes.com/docs/USB_IR_Toy_firmware_update