Hey Gary,
this thread is not about problems during flashing, it is about 1.2.1 firmware issues and the original poster found not to get enough attention and re-posted it again and again in new threads. Problems with 1.2.1 should be reported here.
If you want to report about problems with flashing, this does not rely to problems with 1.2.1 since an operating system disk image is just a file, and it is just written to a SD card. This procedure does in no way depend of which file it is or which Onefinity version. However as I understand your problem is solved since you replaced the SD card and it worked, so you simply had a defective SD card.
By the way I am just an ordinary user (trust-level “Regular” as of this writing).
By the way, if you want to delete a post, there is a little trash can under your posts. The posts then disappear completely after a while.