Fresh install with full disk erase of macOS Big Sur beta 4
OpenCore DBG-061-2020-08-05 compiled with Xcode 11.6

Excerpt from attached opencore.txt:

90:352 04:133 OCB: Should boot from 6. Recovery 11.0 (T:4|F:1|G:0|E:0|DEF:0)
90:501 00:149 OCRAM: Extent allocation of 877555766 bytes (A) gave 100000000
100:558 10:056 OCRAM: SHA-256 Digest is: 56CA14B29FC71637CE5EB10BC4EE76E6D0E9F565202A80DD2A30961A65B4301E
100:671 00:113 OCB: Found chunklist BaseSystem.chunklist for DMG BaseSystem.dmg[10]
110:779 10:108 OCDI: Built DMG DP: VenHw(957932CC-7E8E-433B-8F41-D391EA3C10F8,00000000)/MemoryMapped(0xA,0x100000000,0x100001000)/DMG_00000000344E7036.dmg/VenMsg(004B07E8-0B9C-427E-B0D4-A466E6E57A62,36704E3400000000)
111:807 01:027 OCB: Failed to get bootable file off DMG
111:820 00:012 OCB: Failed to retrieve boot file from DMG
111:836 00:016 OCB: LoadImage failed - Unsupported

config.plist.zip
opencore-2020-08-06-164532.txt