Help retrieving /flash/secure/key.txt from Jio Fiber Box JCO500

[rbhorse]

I've followed the guide at https://github.com/JFC-Group/JF-Customisation/blob/main/Instructions/Get-Any-File-From-JF-ONT-Home-Gateway.md but I havent been able to figure out how to get the encryption key

Model: JCO500 (Square white box)
Firmware version: FXCTF1_JCO500_R3.13
Serial: RUFOTCC000*****

Things I tried (and resulting error screenshot below):
Used Postman with configuration specified on the page
Used Zap Proxy, intercepted the request and edited to align with instructions given on the page

What might help:
A known-good cURL command where I need to substitute only the current token and TeamF1Login as a sanity check.
Information on what the USB label should look like; I've set the label for the FAT32 drive to SSS using Windows 10, should it appear with the same name under 'Administration'? Mine appears by the OEM name (I tried both names while sending the requests)-

If all fails, any disassembly instructions? What kind of chip is the firmware stored on? I have a firmware flasher I can put to use if its a SOIC8. Does the box have hidden screws beneath the giant grey circular rubber pad or should I just pull on the top hat harder?

[itsyourap]

Are you even sure your router uses the /flash/secure/key.txt for encrypting backup?
That was used almost one year ago and now new methods are used.

[itsyourap]

Did you try to use the https://github.com/JFC-Group/JF-Customisation/blob/main/keyguesser.py ?

[rbhorse]

Did you try to use the https://github.com/JFC-Group/JF-Customisation/blob/main/keyguesser.py ?

This did not work.
I will probably just dump it from the flash chip in a couple of days