On 9o firmware but have had these things happen on 9n firmware too:
1. When hooked into a breadbin C64 (UK PAL), i'm finding that an SD2IEC can't seem to be active in any capacity at the same time as having drive emulation on via cart port with the TCV2 drive ID at 9 (i don't have the cable to hook the TCV2 into the IEC port to test IEC connection of the TC) without major issues in terms of access because SD2IEC reads become intermittent at best and almost impossible at worst. once i turn off internal connection of the emulated drive, it allows the SD2IEC to work correctly but without the emulated drive. same goes if i make the emulated drive 8 and the sd2iec drive 9.
2. I'm finding that a couple of demos refuse to load correctly at all - desert dream reaches the "loading demo..." screen and just infinite loads. and edge of disgrace just crashes. i've checked the d64's work in VICE just fine so it's not my images and i've also tested with stock C64 and jiffydos kernal and 1541 drive roms and with/without any fastload carts with no change in DD and with varying points of crashing in EOD.
3. is there any easy way to copy files between SD2IEC and TCV2 on hardware rather than SD card juggling via PC? (i.e. create a blank D64 either on SD2IEC via TCV2 or create a blank D64 on TCV2 and then copy over to SD2IEC). i've tried the file creation basic programs i found on (i think) lemon64 and while they work, i found that they mess around with the file order on the sd2iec and i then have to take the sd card back to pc and fix it there (i know the sd2iec isn't your hardware so i'm not expecting for you to come up with fixes for the file order thing)
4. Does the MMC64 functionality have any sort of advantage over the built in TCV2 file browser (especially when paired with an SD2IEC)?