Hi Jonathon,
Everything is at the proper version to do a Pegasus 1 firmware update.
But the error, "unsupported management command" is an error I have not seen before and I don't think you should see this kind of an error in a firmware update.
Do you have more than one Pegasus attached?
Please try updating using the CLI. Open a Terminal and use the promiseutil command.
Since your screenshot shows the file in the downloads folder, you can use the same form of command, but you will have to change the username in the path to your username. If you are not sure what your username is use the terminal command whoami.
promise@promises-Mac-mini Downloads % whoami
promise
ptiflash -f /Users/YOURUSERNAME/Downloads/R\ SI\ 504000061.img
So after running promiseutil you only need to use the command above.
This is what a firmware update session looks like. The text you will enter have been made bold.
promise@promises-Mac-mini Downloads % promiseutil
-------------------------------------------------------------
Promise Utility
Version: 4.06.0000.01 Build Date: Aug 4, 2021
-------------------------------------------------------------
List available RAID HBAs and Subsystems
===============================================================================
Type # Model Alias WWN Seq
===============================================================================
hba 1 * Pegasus R4 2000-0001-5530-6d27 1
Totally 1 HBA(s) and 0 Subsystem(s)
-------------------------------------------------------------
The row with '*' sign refers the current working HBA/Subsystem path
To change the current HBA/Subsystem path, you may use the following command:
spath -a chgpath -t hba|subsys -p <path #>.
Type help or ? to display all the available commands
-------------------------------------------------------------
cliib> ptiflash -f /Users/promise/Downloads/R\ SI\ 504000061.img
Start transferring image, please wait ...
Flash image has been successfully transferred.
Start flashing image, please wait ...
... 100 percent completed...
Flash Completed.
cliib>
You will have to reboot the Pegasus for the new firmware to load.