Japan's largest mobile phone operator, NTT DoCoMo, has found a software glitch in its latest web-linking phone after 230,000 were sold.
The latest in a series of DoCoMo mobile phone bugs causes the phone to turn off when accessing some websites.
NTT DoCoMo is notifying the owners of the P503i model by mail and preparing to replace the defective handsets.
"When the power is turned back on, data stored in the phones may be erased, such as telephone numbers, e-mail addresses, downloaded programs, melodies and bookmarks," said NTT DoCoMo spokesman Mr Norio Hasegawa.
The phone is one of two models on sale with the "i-appli" feature, an upgrade of the popular "i-mode" Internet service offered by NTT DoCoMo.
I-mode, which has attracted more than 18 million users, allows users to exchange e-mail and look at Internet sites especially designed for cellphones, such as the news, restaurant searches and cartoon images.
The glitch in the P503i happens only when i-mode is set to show a minimised image and can be avoided by showing images full-size or not showing them at all.
Earlier this week, NTT DoCoMo said it would replace some 100,000 mobile phones for software glitches found on four handset models, manufactured by Sony, Japan Radio, Hitachi and Sweden's Ericsson.