The teardown was done by XYZone, a Shenzhen-based company that disassembles smartphones and identifies the suppliers of their components. The biggest surprise was that some parts from US companies were still ending up in the newest Huawei smartphone, despite the States all but banning its companies from selling to the Chinese tech company.

The P40's radio-frequency front-end modules were, according to XYZone's teardown analysis, produced by Qualcomm, Skyworks, and Qorvo, three American chip companies. RF front-end modules are critical parts of the phone that are attached to the antennas and required to make calls and connect to the internet.

The Qualcomm component is covered by a license from the US Commerce Department, according to a person familiar with the company.  The "Entity List" designation means that companies have to apply for a licence to export any US-origin technologies to Huawei.

The US government has granted a "temporary general licence" to its companies, allowing them to sell to Huawei to service existing products -- helping clients such as telecoms carriers that may need to replace parts of their wireless equipment. But the general licence does not cover sales for the purpose of making new products, such as the P40 smartphone. For that, companies must seek individual licences, and the Department of Commerce has not said which ones it has granted them to.

A spokesperson for Huawei said the company has "always complied with any export control regulations of various countries, including the United States" and that "all the product materials are obtained legally from our global partners, and we insist on working with our partners to provide consumers with high quality products and services"'

Also missing from the P40 are parts from US chipmaker Micron. "Micron made the storage devices called NAND flash memory chips for some batches of last year's P30 smartphone, and South Korea's Samsung made the same chips for other batches", reports Ars Technica. "The FT's copy of this year's P40 Pro appears to have only Samsung NAND flash memory chips."