The only Siglent device I have, is a cheap scope SDS 1202X-E. I also had problems with a FW update in between, so that I went back to the oldest FW, as I couldn't save pictures... Luckily, I have never had a boot issue, like the users of a Siglent SDM DMM, despite the old FW on my 1202X-E.
The latest FW, however, solved this USB problem, so that I have nothing to complain any more, apart from the fact, that I haven't used the scope for 2-3 years... Ha ha ha...
Unfortunately, I don't know, whether this is a good idea, to try the same thing I did with my scope, going also back to an older FW, when it may does not boot any longer afterwards...thus you need a special medicine, which only tautech distributes via this EEVBlog-Forum via PM, which is also quite confusing...
Considering the latest datasheet of the Siglent SDM 3055X-E, I posted above, you should have at least a claim to get your money back, to buy another brand, because this is definitely not a fine move by Siglent...or they should resolve this 240.000 counts thingie, when it is done by mistake.
Best wishes for your decision - or maybe tautech has a further solution for you?!
Cheers!