TOKYO, June 21 (Reuters) - Japan"s Toshiba Corp (6502.T) on Monday promised to drastically improve corporate governance and, ahead of a crucial shareholder meeting this week, released an internal report that had cleared management of wrongdoing. An independent report published this month found the company colluded with government officials, while the company"s internal report in February cleared management of accusations it pressured shareholders to back board appointments. read more Chairman Osamu Nagayama will seek to retain his post at a shareholder meeting on Friday in the face of pressure from some shareholders to resign. The release of the internal report on Monday could help persuade some that when Nagayama opposed shareholders, who called for the internal inquiry in March, he was acting in good faith. Shareholder advisory groups Institutional Shareholder Services Inc and Glass Lewis have both recommended that Nagayama not be reappointed. Toshiba"s No.2 shareholder, Singapore-based 3D Investment Partners also opposes his nomination.