https://phys.org/news/2018-06-china-zte-resumption-hong-kong.html

The decision came after US officials said ZTE had failed to take action against staff who were responsible for violating trade sanctions against Iran and North Korea. The company was fined $1.2 billion last year for those violations.

The move in April put the company's future in doubt and it became a key issue in a wider trade spat between Washington and Beijing.