Unable to build PSP version

I tried to rebuild RA on my own using official guide. Pulled repo.

But command:
make -f Makefile.psp1.salamander
results error at ../../frontend/drivers/platform_psp.c:66:10 about missing "../../bootstrap/psp1/kernel_functions.h" file.
This file exists only in subdirectory kernel_functions_prx:
../../bootstrap/psp1/kernel_functions_prx/kernel_functions.h

Another way from guide is to use this:
cd dist-scripts && ./dist-cores.sh psp1
It results another error:
ls: unable to access '*_psp1.a': No such file or directory
(translation can be a bit incorrect)

UPD:
Seems like ./dist-cores.sh psp1 copies some files. After it I was able to run
make -f Makefile.psp1.salamander
without any visible errors, but still
make -f Makefile.psp1
exits with code 1:
/usr/local/pspdev/lib/gcc/psp/9.3.0/../../../../psp/bin/ld: cannot find -lretro_psp1

Steps to reproduce the bug

1. git clone https://github.com/libretro/RetroArch.git retroarch
2. cd retroarch
3. make -f Makefile.psp1.salamander
   OR
4. cd dist-scripts && ./dist-cores.sh psp1

Version/Commit

• RetroArch: Latest version, commit df3af35ee46fdd91dec7ef51d9b4493802b9ea56.

Environment information

• OS: Ubuntu 16.04 32-bit
• SDK from https://github.com/pspdev/psptoolchain

Reproduce the PSP build commands from the issue, then inspect frontend/drivers/platform_psp.c, bootstrap/psp1, dist-scripts/dist-cores.sh, and the Makefile.psp1 targets. Confirm whether the header and retro_psp1 library are produced or referenced from the expected locations, and consider the build fixed when both PSP make commands complete successfully.