coreboot

My X200s with panel LTD121EQ3B and 2x4GB identical RAM running a coreboot-4.19-937-g0b192d3238 built for X200, configured with the attached x200s.cfg, having the following contents, crashed with beeping after graphic init (screen lights), and before booting from the grub-based payload.

FMAP REGION: COREBOOT
Name                           Offset     Type           Size   Comp
cbfs_master_header             0x0        cbfs header        32 none
fallback/romstage              0x80       stage           69240 none
cpu_microcode_blob.bin         0x10f80    microcode       49152 none
fallback/ramstage              0x1cfc0    stage          130413 LZMA (297648 decompressed)
config                         0x3cdc0    raw              3019 LZMA (9596 decompressed)
revision                       0x3d9c0    raw               716 none
build_info                     0x3dcc0    raw               101 none
fallback/dsdt.aml              0x3dd80    raw             14999 none
cmos.default                   0x41880    cmos_default      256 none
cmos_layout.bin                0x419c0    cmos_layout      1696 none
fallback/postcar               0x420c0    stage           33912 none
data_ccfl.vbt                  0x4a580    raw              1501 LZMA (3854 decompressed)
data_led.vbt                   0x4abc0    raw              1439 LZMA (3863 decompressed)
(empty)                        0x4b1c0    null             7140 none
fallback/payload               0x4cdc0    simple elf    7123033 none
(empty)                        0x717e80   null           853028 none
bootblock                      0x7e82c0   bootblock       31488 none

This problem will disappear if I remove one DIMM, remove vbt files from CBFS, or enable EHCI debug with FT232H, which makes me unable to catch it.