MarkIV - can't update firmware

[tb2k]

I bought the Mark4 back in 2012 and played with it and then it got into a box and i moved ... yada yada

So I just found the little guy again and its still on version 2.7. I was able to find and download the newer firmware but it doesn't upgrade (including 3.0). I'm getting an error that says "MD5sum does not match!" and gets out.

I understand that the Infusions wouldn't update over the internet and i can update them thru a USB device, but all the infusions go back to 2.8.1 only. Can someone help, please?

[tb2k]

Ok, so i was able to upload the bin file to the /tmp folder and ran the sysupdate manually to 2.8.1 and it seems to upgrade and reboots. 

I then login again and its still at 2.7.0. And ofcourse the /tmp/ folder is wiped out.

So... back to square 1. I think its still looking to do a checksum test. Can i bypass that?