Bloomberg was wrong here.
Huawei routers had Telnet installed on them, which is completely standard. Vodafone, the company that was supposedly targeted, disputed Bloomberg's characterization of standard diagnostic software as a "backdoor":
> The 'backdoor' that Bloomberg refers to is Telnet, which is a protocol that is commonly used by many vendors in the industry for performing diagnostic functions. It would not have been accessible from the internet.[1]
This is not the first time Bloomberg has made sensationalist claims about Chinese backdoors. This one fell apart with even the lightest of scrutiny. One wonders if the Bloomberg reporter even understood what Telnet is.