Linker unresolved references

[nottledim]

Recently updated arduino to 1.8.16 and installed esp 2.0.0. I now get errors like this:

/home/dick/.arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/gcc8_4_0-esp-2021r1/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld: sketch/ulp-ds18b20s.ino.cpp.o:(.literal._Z5setupv+0x94): undefined reference to `ulp_rcode'

A few reports of this problem exist but they don't help.

Why do I get these errors from the linker? What can I do to fix it?

[IAMAHGK]

Recently updated arduino to 1.8.16 and installed esp 2.0.0. I now get errors like this:

/home/dick/.arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/gcc8_4_0-esp-2021r1/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld: sketch/ulp-ds18b20s.ino.cpp.o:(.literal._Z5setupv+0x94): undefined reference to `ulp_rcode'

A few reports of this problem exist but they don't help.

Why do I get these errors from the linker? What can I do to fix it?

Hey I uninstalled the version of esp32 in board manager and downloaded the 1.0.0 version.
This error was removed although the undefined reference error is still there.