I am also getting error 34 from UFED 4PC 18.104.22.168 after the checkm8 exploit fails after five minutes on an iPhone7 and an iPhone 6S Plus. iTunes reports DFU mode is good on both iPhones, so it’s not my technique. I suspect the Windows 10 Pro version (1909) clean installed on my workstation may be the problem. What version of Windows 10 are you examiners running that succeed and get FFS extractions with those big DAR output files? I’m hearing versions 1909 and 1903 may be challenged.