Mine doesn’t seem to handle resistance metering correctly, either before or after the firmware update. With no leads connected, and the top channel set to Showing Aux Voltage DC/Ohms above and A/1.2V/V below, the resistance displayed slowly changes over time (in a stable environment). As an exmaple, while I typed this comment I watched it drift from -0.65 to -0.72 and it’s still changing in that same direction. The second channel is set to Votage DC/V and A/60V/V and sitting right at 0.0000 or -0.0001 and stable. Checking known resistance resistors and a few handy potentiometers side by side show my other 2 meters match, but the mooshimeter doesn’t seem to have any idea what to do with resistance :)
If I plug in leads and check DC voltage between V/C and a slightly old 9V battery, it reads accurately against another meter, and same for checking AC voltage. Given the resistance readings seem to be acting odd, I haven’t done any current measurements.