On a recently purchased LANTurtle SD with the new turtle3 firmware following the below guide.
Given that I can install packages such as curl it looks like there's an issue with the repo. Given the lack of modules in the TUI I suspect that the new firmware does not put them in the expected locations.
The link here appears to add the modules, though obviously the entire pkg update does not complete successfully.
Note that there are some typos in this guide.
1. Instructs to install turtle-2.bin instead of turtle-3.bin
2. MD5 checksum when sha256 provided
3. No sha256 present on turtle (can use either busybox or coreutils-sha256sum)