US billionaire investor Carl Icahn has stepped up his efforts to win a seat on Motorola's board by placing a full page advert in a US newspaper.
Carl Icahn is pressing for change at Motorola
Mr Icahn, who with associates owns about 3% of the mobile phone firm, made the plea in the Wall Street Journal.
Motorola had "suffered a critical failure in oversight and leadership," he said in the advert.
Tough competition has hit the firm's handset sales, resulting in it making a loss in the first three months of 2007.
Earlier this year, Mr Icahn announced that he would put himself up for a board post at Motorola's annual general meeting, which is scheduled for 7 May.
In the advert, he said it was "absolutely necessary" for the company that a major shareholder was represented on the board.
He added that the firm had "stumbled badly" under current chief executive Ed Zander.
Motorola responded to the advert, saying it had been listening to Mr Icahn since he became a shareholder.
It added it had offered to work with him to identify a "mutually acceptable" candidate for the board position, but said that the investor had declined.
In recent years Mr Icahn has snapped up stakes in US media group Time Warner and building materials maker Temple Inland.
At each company he suggested radical reforms - such as selling off assets - that would either lift the group's shares or create more value for shareholders.
Last year Mr Icahn made an unsuccessful bid to buy Korean tobacco firm KT&G with Warren Lichenstein, head of fund Steel Partners II. The $10bn bid included plans for the sale of some of the firm's assets.