I've TFTPed 5.1.6 onto four different 2032s. Two were Unbranded Hikvision from Nelly's, two WERE Chinese from Wrightwood but I applied the mtd hack thanks to @whoislooking. Since those went well, maybe I became too confident thinking I could downgrade this DS-2CD2332-i5 USA 5.2.0 to 5.1.6. After...