When the U.S. put Huawei on the entity list in 2019 because it was considered a national security threat, it blocked the company from accessing its U.S. supply chain. And that meant that Huawei was no longer able to license Google Mobile Services for its Android handsets. Huawei needed to develop its own ecosystem, which it did, and also needed to come up with a replacement OS for Android, which it also did.