Helm v2a will not enter maskrom mode

[8ICE8]

I'm hoping that someone can help me out. Everyday desktop computer I'm using is LinuxMint 21 based on Ubuntu 20.04, running Cinnamon desktop.

I have a Helm v2a and finally found a use case for this device (since I've already found new email that I trust), downloaded the requisite files, and successfully installed rkdeveloptool and dependencies.

All provided instructions on this site were followed TO A TEE for entering maskrom at least 10 times and the device will not enter it. I'm using the power cable that came with the Helm device, a CAT 6 cable that I hijacked from another device currently on the network, and a USB-C cable that I use for many different devices for both charging and data transfer - in other words, I trust that they're up to the task and can rule out the physical layer WRT cabling matters.

Is there a nuance to this technique or difference from the given instructions that is not mentioned?

Is there an alternative method - even setting jumpers? I've opened the case and noticed no backup batteries were installed, and not sure if this would make a difference. And BTW, what type of batteries would be needed for backup power?

Thank you in advance for any assistance!