The new offer comes as separate sources say the embattled Japanese conglomerate and Western Digital are struggling to strike a deal ahead of their self-imposed deadline of Thursday.

Toshiba has been scrambling to sell its flash memory unit – the world’s No. 2 producer of NAND chips – to cover billions in losses at its bankrupt U.S. nuclear business Westinghouse.

Toshiba’s relationship with Western Digital, its joint venture partner for its chip business, has been rocky throughout the auction process – to the point that other bidders were favored first while the U.S. firm has also initiated legal action that threatens to derail any deal that does not have its consent.

The revised offer is worth some 2 trillion yen ($18.2 billion). Bain and South Korean chipmaker SK Hynix will be responsible for 1.1 trillion yen, while Apple will provide up to 400 billion yen and Japanese banks will give around 600 billion yen in support, one of the sources said.

The proposal also calls for Toshiba to be part of the deal, investing 200 billion yen, the source said.

A Bain-led group had previously been chosen by Toshiba as its preferred bidder. But those talks lapsed as Japan government investors who had been part of that consortium told Toshiba they were reluctant to close a deal in the face of the legal risks posed by Western Digital’s demands.

Bain’s new offer is designed to get around that problem as it will invite the state-backed investors – the Innovation Network of Japan (INCJ) and the Development Bank of Japan (DBJ) – to invest in the business only after any arbitration with Western Digital is settled, the source said.

The bid trumps the 1.9 trillion yen offered by the Western Digital-led consortium, which also includes U.S. private equity firm KKR & Co. Banking sources have previously said, however, that Western Digital was working to get its proposal up to 2 trillion yen.

Bain’s revised bid was first reported by Japanese broadcaster NHK which said it would be structured so that Bain and Toshiba would each hold 46 percent of the unit.

The sources declined to be identified as talks concerning the auction were private.

Toshiba, Bain, SK Hynix, Western Digital and INCJ declined to comment. Representatives for Apple, DBJ and KKR were not immediately available for comment.

People familiar with the matter have said Toshiba and Western Digital are bickering over the size of any potential stake to be held by the U.S. firm in the chip unit. For now, Western Digital plans to invest only through convertible bonds.

But Toshiba wants to reach a deal soon and it is not clear if it will give serious consideration to Bain’s new proposal.

Failure to clinch a deal in the next few weeks could mean that it may not clear all necessary regulatory approvals by the end of the financial year in March. That would likely lead to Toshiba reporting negative net worth for two years in a row, increasing its chances of being delisted.