Just added new files for Kvarta BF533-PERCH board.
(include bf533_perch.c)
Success make for bf533-perch.
After this save bf533-perch_defconfig for buildroot and
BF533-PERCH_defconfig for linux kernel.
OK. Network support - off. CPU CLK = 25000000. Board name = BF533-PERCH.
New file sdc is small script for configuration update.
Build OK: MTD, init RAM fs - off; MMC, MMC_SPI, EXT2_FS on.
Rewrite output/linux-custom/.config from TDN.
Run sdc - ok, run make - ok.