An anonymous reader writes: For several years now, Panasonic and NEC have released Linux-based feature phones on the Japanese cellular carrier NTT Docomo network. However it seems that they may be violating Section 3 of the GPL by requiring a valid IMEI number to receive the source code. Panasonic's download site. NEC's download site. The GPL requires that the source either accompany the product or that it be made available to any third party upon request. Have these manufacturers broken the license agreement by demanding additional requirements?