Huawei's beleaguered smartphone business has taken another blow, with the SD Association pulling its support. That means that Huawei can't use microSD in its phones.

The move comes as the latest play in the on-going trade stand-off between the US and Huawei, which all started on 16 May when the company was added the US Bureau of Industry and Security Entity List. 

That forbids US companies from trading technologies with Huawei and saw the likes of Qualcomm, Google, Arm and others having to comply with the order and cease business. 

This unfolding story reveals the uncertainty of operating in a global market where you're depending on components from an international supply chain and will perhaps send a stark warning to others in a similar position: how self-sufficient are you? 

For Huawei, however, this latest move adds some context to an announcement the company made in 2018. At the launch of the Huawei Mate 20 Richard Yu, CEO of Huawei's device business announced a new memory card format.

The format was called NM, a smaller card that fits into a SIM card sized slot on a phone. It allows the company to offer a phone that's either dual SIM or single SIM with NM expandable using the same shaped tray. 

At the time it was seen as a rather unnecessary move - it means that you can't buy a cheap microSD card or use one you already have - but that move might now be more significant, meaning that Huawei can use that format across devices rather than microSD.

Of course, we don't know if there's any intellectual property of the SD Association in the NM card which could cause a problem, but perhaps this small announcement in 2018 was part of Huawei preparing itself for future self-sufficiency.