Had exactly the same issue. Trying to upgrade S10 from a very old firmware 5.1.028 to the latest one : 7.1_033
I have 3 units dead. I cannot contact Wyse Support because these units are not under maintenance anymore ;-(
Does anyone found a solution to "resurrect" them like said VantageOne ?
I spoke with the french support about this issue this afternoon.
They could not tell me why I had this issue, but the upgrade from firmware v5 to v7 is not supported. This is mentioned in the knowledge base on their website, but not in the release notes.
The good way is to upgrade from v5 to v6 and then from v6 to v7. I don't want to try because i don't have spare units anymore. But it seems very strange that upgrade v5->v7 destroy the unit and v5->v6->v7 is ok...