Western Digital, which jointly runs Toshiba’s main semiconductor plant, has been feuding bitterly with its Japanese partner over the sale of the world’s No. 2 producer of NAND chips and has sought a U.S. court injunction to prevent any deal that does not have its consent.

The tensions come amid uncertainty over whether Toshiba can sign as planned a definitive agreement with its preferred bidder—a group led by the Japanese government and including U.S. private equity firm Bain Capital—by Wednesday, the day of its annual shareholders meeting.

The conglomerate is rushing to sell the unit to cover billions of dollars in cost overruns at its bankrupt Westinghouse nuclear unit and to dig itself out of negative shareholders’ equity that could lead to a delisting.

The preferred bidder consortium’s 2 trillion yen ($18 billion) offer calls for a state-backed fund, INCJ, to pay 300 billion yen for a majority stake in terms of voting rights while Bain will put up more but not hold a majority, sources have said – an unusual arrangement that satisfies the Japanese government’s desire to keep the firm under domestic control.

Bain will invest 850 billion yen, which will include some equity with voting rights as well as some preferred shares, while South Korea’s SK Hynix will provide half the amount Bain plans to put up in the form of financing, the sources said.

The Development Bank of Japan and the core unit of the Mitsubishi UFJ Financial Group are also part of the consortium.

Western Digital said in a June 25 letter to Toshiba’s board that SK Hynix’s participation in the consortium increased the likelihood of technology leakage to the rival chipmaker, adding that the winning bid did not appear to be bigger than its own offer.

“I must make it clear that Western Digital will not consent to a transaction with the proposed consortium,” CEO Stephen Milligan said in a letter, which was seen by Reuters.

“This potential course of action would make further litigation inevitable,” the letter said.

The letter comes after Toshiba CEO Satoshi Tsunakawa said on Friday it was open to talks with Western Digital, although it was not planning to make the first move.

Tsunakawa also argued that SK Hynix would not be holding any equity and would not be involved in management – an arrangement that was unlikely to raise regulatory red flags and would prevent leaks of key technology information.

SK Hynix declined to comment on the matter on Monday. The chipmaker, which is relatively weak in NAND chip technology, has said previously that it had decided to join the consortium as it sees business opportunities. Representatives for Bain could not be reached for comment outside regular office hours.

Concerns about SK Hynix’s participation have also been voiced by some members of Toshiba’s board, sources familiar with the matter said on Monday, declining to be identified as discussions were confidential.

Toshiba has previously sued its South Korean rival over the suspected theft of data related to flash memory technology—a claim that was settled by SK Hynix for $278 million in December 2014.

Tsunakawa said on Friday he did not expect any changes to the make-up of the consortium before June 28, adding that Western Digital’s offer had not found favor on price and because the U.S. firm wanted to take control of the unit.

Western Digital expects a U.S. court ruling on its request for an injunction on July 14.