I think making fat32 partition active on flash drive was the reason because I only remember this as a requirement for ntfs bootable flash drive(like the ones made by MS own usb boot tool in win 7).Also I think setting your mobo to legacy/mbr mode does not remove its ability as uefi to read fat32 non-active partition flash drive.
Just formatting the USB FAT32 is enough for normal usage, never made it active before, always worked without it. When 3rd party software is used on the usb, the user should know how to work around it.
Yeah, the active setting is still there on the now working drive/partition (so it doesn't hurt) via diskpart, but it is rarely 'required' any more. My old 7GB Sandisk Cruiser may be the problem itself. It's always been a little glitchy. I have newer, better ones, but I'm using them for other things. Anyway, got it working, thanks for the tip.