Hello, i build a custom firmware (stable - version 18.06.5 for my Wrt32x) at the end i have a warning message : WARNING: Applying padding in /home/nonosch/openwrt/bin/packages/arm_cortex-a9_vfpv3/packages/Packages to workaround usign SHA-512 bug! i search on this forum but i didn't find what to …

You don't need to do anything. See also https://git.openwrt.org/?p=openwrt/openwrt.git;a=commitdiff;h=e1f588e446c7ceb696b644b37aeab9b3476e2a57 Signature check failed after clean installation