Hi, I tried to install today's (24.7.) amd64 snapshot on two machines. Both simply rebooted during the kernel init, i.e., when booting install.fs/iso (tried with USB and CD). (amd64/6.3 worked fine.)
On one I was able to connect a serial port; output below. /Robert OpenBSD 6.3-current (RAMDISK_CD) #128: Tue Jul 24 05:47:12 MDT 2018 dera...@amd64.openbsd.org:/usr/src/sys/arch/amd64/compile/RAMDISK_CD real mem = 17091780608 (16299MB) avail mem = 16569995264 (15802MB) mainbus0 at root bios0 at mainbus0: SMBIOS rev. 3.0 @ 0x8d99a000 (63 entries) bios0: vendor American Megatrends Inc. version "4401" date 03/05/2018 bios0: ASUSTeK COMPUTER INC. P10S-I Series acpi0 at bios0: rev 2 acpi0: tables DSDT FACP APIC FPDT FIDT MCFG HPET LPIT SSDT SSDT SSDT DBGP DBG2 SSDT HEST SSDT UEFI SSDT DMAR EINJ ERST BERT acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat cpu0 at mainbus0: apid 0 (boot processor) cpu0: Intel(R) Core(TM) i3-6100 CPU @ 3.70GHz, 3692.76 MHz cpu0: FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,NXE,PAGE1GB,RDTSCP,LONG,LAHF,ABM,3DNOWP,PERF,ITSC,FSGSBASE,SGX,BMI1,AVX2,SMEP,BMI2,ERMS,INVPCID,MPX,RDSEED,ADX,SMAP,CLFLUSHOPT,PT,IBRS,IBPB,STIBP,SENSOR,ARAT,XSAVEOPT,XSAVEC,XGETBV1,XSAVES,MELTDOWN cpu0: 256KB 64b/line 8-way L2 cache cpu0: apic clock running at 23MHz cpu0: mwait min=64, max=64, C-substates=0.2.1.2.4.1, IBE cpu at mainbus0: not configured ioapic0 at mainbus0: apid 2 pa 0xfec00000, version 20, 120 pins acpiprt0 at acpi0: bus 0 (PCI0) acpiprt1 at acpi0: bus 1 (PEG0) acpiprt2 at acpi0: bus -1 (PEG1) acpiprt3 at acpi0: bus -1 (PEG2) acpiprt4 at acpi0: bus -1 (RP09) acpiprt5 at acpi0: bus -1 (RP10) acpiprt6 at acpi0: bus -1 (RP11) acpiprt7 at acpi0: bus -1 (RP12) acpiprt8 at acpi0: bus -1 (RP13) acpiprt9 at acpi0: bus -1 (RP01) acpiprt10 at acpi0: bus -1 (RP02) acpiprt11 at acpi0: bus -1 (RP03) acpiprt12 at acpi0: bus -1 (RP04) acpiprt13 at acpi0: bus 2 (RP05) acpiprt14 at acpi0: bus 3 (BR52) acpiprt15 at acpi0: bus 4 (RP06) acpiprt16 at acpi0: bus 5 (RP07) acpiprt17 at acpi0: bus -1 (RP08) acpiprt18 at acpi0: bus -1 (RP17) acpiprt19 at acpi0: bus -1 (RP18) acpiprt20 at acpi0: bus -1 (RP19) acpiprt21 at acpi0: bus -1 (RP20) acpiprt22 at acpi0: bus -1 (RP14) acpiprt23 at acpi0: bus -1 (RP15) acpiprt24 at acpi0: bus -1 (RP16) acpiec0 at acpi0: not present acpicpu at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpipwrres at acpi0 not configured acpitz at acpi0 not configured acpitz at acpi0 not configured "PNP0B00" at acpi0 not configured "INT3F0D" at acpi0 not configured "PNP0A05" at acpi0 not configured "PNP0C0E" at acpi0 not configured "INT33A1" at acpi0 not configured "PNP0C0C" at acpi0 not configured "INT340E" at acpi0 not configured "PNP0C0B" at acpi0 not configured "PNP0C0B" at acpi0 not configured "PNP0C0B" at acpi0 not configured "PNP0C0B" at acpi0 not configured "PNP0C0B" at acpi0 not configured pci0 at mainbus0 bus 0 pchb0 at pci0 dev 0 function 0 "Intel Core 6G Host" rev 0x07 ppb0 at pci0 dev 1 function 0 "Intel Core 6G PCIE" rev 0x07: msi pci1 at ppb0 bus 1 nvme0 at pci1 dev 0 function 0 vendor "Intel", unknown product 0xf1a5 rev 0x03: apic 2 int 16, NVMe 1.2 nvme0: INTEL SSDPEKKW128G7, firmware PSF121C, serial BTPY80950HWL128A scsibus0 at nvme0: 1 targets sd0 at scsibus0 targ 0 lun 0: <NVMe, INTEL SSDPEKKW12, PSF> SCSI4 0/direct fixed sd0: 122104MB, 512 bytes/sector, 250069680 sectors xhci0 at pci0 dev 20 function 0 "Intel 100 Series xHCI" rev 0x31: msi, xHCI 1.0 usb0 at xhci0: USB revision 3.0 uhub0 at usb0 configuration 1 interface 0 "Intel xHCI root hub" rev 3.00/1.00 addr 1 "Intel 100 Series Thermal" rev 0x31 at pci0 dev 20 function 2 not configured "Intel 100 Series MEI" rev 0x31 at pci0 dev 22 function 0 not configured ahci0 at pci0 dev 23 function 0 "Intel 100 Series AHCI" rev 0x31: msi, AHCI 1.3.1 ahci0: port 0: 6.0Gb/s ahci0: port 1: 6.0Gb/s ahci0: port 4: 6.0Gb/s ahci0: port 5: 6.0Gb/s scsibus1 at ahci0: 32 targets sd1 at scsibus1 targ 0 lun 0: <ATA, WDC WD80EFZX-68U, 83.H> SCSI3 0/direct fixed naa.5000cca263cd6db9 sd1: 7630885MB, 512 bytes/sector, 15628053168 sectors sd2 at scsibus1 targ 1 lun 0: <ATA, WDC WD80EFZX-68U, 83.H> SCSI3 0/direct fixed naa.5000cca263cd54d1 sd2: 7630885MB, 512 bytes/sector, 15628053168 sectors sd3 at scsibus1 targ 4 lun 0: <ATA, WDC WD80EFZX-68U, 83.H> SCSI3 0/direct fixed naa.5000cca263cd6c3d sd3: 7630885MB, 512 bytes/sector, 15628053168 sectors sd4 at scsibus1 targ 5 lun 0: <ATA, WDC WD80EFZX-68U, 83.H> SCSI3 0/direct fixed naa.5000cca263cd54df sd4: 7630885MB, 512 bytes/sector, 15628053168 sectors ppb1 at pci0 dev 28 function 0 "Intel 100 Series PCIE" rev 0xf1: msi pci2 at ppb1 bus 2 ppb2 at pci2 dev 0 function 0 "ASPEED Technology AST1150 PCI" rev 0x03 pci3 at ppb2 bus 3 vga1 at pci3 dev 0 function 0 "ASPEED Technology AST2000" rev 0x30 wsdisplay1 at vga1 mux 1: console (80x25, vt100 emulation) ppb3 at pci0 dev 28 function 5 "Intel 100 Series PCIE" rev 0xf1: msi pci4 at ppb3 bus 4 em0 at pci4 dev 0 function 0 "Intel I210" rev 0x03: msi, address b0:6e:bf:3a:a0:4d ppb4 at pci0 dev 28 function 6 "Intel 100 Series PCIE" rev 0xf1: msi pci5 at ppb4 bus 5 em1 at pci5 dev 0 function 0 "Intel I210" rev 0x03: msi, address b0:6e:bf:3a:a0:4e "Intel C232 LPC" rev 0x31 at pci0 dev 31 function 0 not configured "Intel 100 Series PMC" rev 0x31 at pci0 dev 31 function 2 not configured "Intel 100 Series SMBus" rev 0x31 at pci0 dev 31 function 4 not configured isa0 at mainbus0 com0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo com0: console com1 at isa0 port 0x2f8/8 irq 3: ns16550a, 16 byte fifo pckbc0 at isa0 port 0x60/5 irq 1 irq 12 pckbd0 at pckbc0 (kbd slot) wskbd0 at pckbd0: console keyboard, using wsdisplay1 fatal protection fault in supervisor mode trap type 4 code 0 rip ffffffff8120d781 cs 8 rflags 10246 cr2 0 cpl 0 rsp ffff80002212d418 gsbase 0xffffffff81868ff0 kgsbase 0x0 panic: trap type 4, code=0, pc=ffffffff8120d781 syncing disks... uvm_fault(0xffffffff818c9438, 0xc80, 0, 1) -> e fatal page fault in supervisor mode trap type 6 code 0 rip ffffffff810db259 cs 8 rflags 10286 cr2 c80 cpl 0 rsp ffff80002212d230 gsbase 0xffffffff81868ff0 kgsbase 0x0 panic: trap type 6, code=0, pc=ffffffff810db259 dump to dev 17,1 not possible rebooting...