"AT&T and Alcatel-Lucent jointly identified a software defect — triggered under certain conditions - that impacted uplink performance for Laptop Connect and smartphone customers using 3G HSUPA-capable wireless devices in markets with Alcatel-Lucent equipment," the company said in a statement.
"This impacts less than two percent of our wireless customer base. While Alcatel-Lucent develops the appropriate software fix, we are providing normal 3G uplink speeds and consistent performance for affected customers with HSUPA-capable devices."
On Tuesday, AppleInsider exclusively reported that, contrary to various Internet speculation, AT&T was not intentionally throttling upload speeds for iPhone 4 users. Some in major U.S. markets such as Los Angeles and New York reported upload speeds of around 100Kbps, well below the capabilities of the HSPA-equipped iPhone 4.
Instead, it was revealed Tuesday that the issues were a result of an unintentional software glitch related to High-Speed Uplink Packet Access in some sections of the country. When working properly, HSUPA can allow uplink speeds of 5.76Mbit/s.