The steps you posted ([Old Spark core] Unable to setup device) performs a factory firmware upgrade and the equivalent CLI command is particle flash --factory tinker
What i posted in ([Spark core] Common issues) contains steps to update an old core as well. I guess the confusion really comes from the typo in the commands i posted. 
I will let @christine, @peekay123, @Moors7 decide what’s the best here and step aside.