S1 MP3 players are a type of digital audio players based on many different kinds of chipsets. The popular ones include Actions and ALi chipsets. They are sold under dozens of different other brand names and in a variety of case designs. The players were very widespread around 2005–2006 and have since been superseded by more advanced models.
Ogg Vorbis support on a small number of models mostly made after 2005, though this is not typically listed on the player's packaging and may come with drawbacks.
Acts as a USB flash drive when connected to a computer, and works without battery charge when connected to a computer or another USB host
Memory capacities between 64 MB and 32 GB. Some higher capacity versions may have a smaller flash memory chip with an edited FAT master table or modified hardware to appear higher in capacity than it really is by writing over previous sectors.
Around 8 hours of battery life on models using a AAA battery. Others have a rechargeable battery which charges via USB host connection. Many turn off automatically when idle for even 30 seconds. Charge duration varies widely between playback and recording modes.
Recording via built-in microphone or FM radio in ADPCM WAV, ACT or VOR formats, and ability to play back these files locally or via Windows Media Player when connected as an MSC device.
ATJ2085 or ATJ2035L as the processor, RAM and the ROM.
Some newer players have a slot for SD/MMC cards of capacities from 32 MB to 4 GB.
Models
There are also several models which carry no brand name or model number on the device or packaging, and a few sold under counterfeit trademarks such as Sony, Samsung, iPod, and others that use the same spelling in their brand name yet different brand styling, with inverse effect to established brands that offer similar or unrelated products.
LG UP3# — Uses the FAT32 filesystem, supports MP3, WMA, ASF and OGG audio formats. Has a built-in USB-rechargeable battery. The detailed FAQ also refers to firmware updates from the LG website.
Available utilities for Microsoft Windows include an ACT to WAV file converter, a basic desktop editor to enter contact details for the device's phone book function and device drivers for Windows 98. An 8 cm CD-ROM containing some or all of these is included with some versions of the device. There are also tools developed by individuals under the Open-Source license, such as s1res ans s1clone that allow the consumer to modify its device by changing bitmaps and text. By using decompilers, it is possible to add and replace features of the device, steps that were described on the wiki page.
Firmware update issues
The firmware used in various S1 MP3 players differs significantly, but this is not widely understood. Problems have arisen as consumers have attempted to upgrade their players using incompatible firmware with a higher version number. This can damage the players almost permanently. However, a 'dead' player can sometimes be recovered by opening it, shorting some pins and uploading a full firmware from the PC. Guides on recovering the players were available on a unofficial website that is offline since 2019, but there is another website that has reuploaded the information, software and firmware for these devices.
