Re: What were the terms of the original deal?
According to Ericsson's press blurb regarding the deal in early 2016, the FRAND royalties payable by Huawei were sekrit.
However, this claim by Samsung regarding the deal between Unwired and Ericsson may explain Unwired's attempt at a stick-up:
"The clause sets a minimum percentage of the net sales revenue of the third party, which must be paid by Unwired Planet to Ericsson. This minimum percentage is payable regardless of whatever royalty rate has been agreed between Unwired Planet and the third party (e.g. if the minimum percentage was 50% and Unwired Planet had agreed a licence based on a royalty of 25% of net sales revenue, then for every £1 sold by the licensee, Unwired Planet would be paid 25p but would still have to pay Ericsson 50p)."
I.e. the bigger the fish Unwired goes after, the higher they have to set the rates, or they'll lose their own shirt to Ericsson. Of course, how you get the third party to cough up their net revenue on a particular product is another matter...