I was able to boot machine which crashed with bsd.sp kernel. Please see message below. That kernel is non-patched kernel as I was running normally bsd.mp kernel. Also I forgot to say in my previous message that I didn't mess with C states (BIOS option). I was also using legacy (not pure UEFI boot) as the the original installation was done on the system which didn't support UEFI boot.
OpenBSD 6.2 (GENERIC) #132: Tue Oct 3 21:18:21 MDT 2017 dera...@amd64.openbsd.org:/usr/src/sys/arch/amd64/compile/GENERIC real mem = 16799846400 (16021MB) avail mem = 16283758592 (15529MB) mpath0 at root scsibus0 at mpath0: 256 targets mainbus0 at root bios0 at mainbus0: SMBIOS rev. 3.0 @ 0xed450 (18 entries) bios0: vendor American Megatrends Inc. version "P1.30" date 04/18/2017 bios0: ASRock J4205-ITX acpi0 at bios0: rev 2 acpi0: sleep states S0 S4 S5 acpi0: tables DSDT FACP FPDT FIDT MCFG DBG2 DBGP LPIT APIC NPKT PRAM WSMT SSDT SSDT AAFT SSDT SSDT SSDT SSDT SSDT UEFI BERT WDAT NHLT acpi0: wakeup devices SIO1(S4) PS2K(S4) UAR1(S4) HDAS(S3) XHC_(S4) XDCI(S4) BRCM(S0) PXSX(S4) RP01(S4) PXSX(S4) RP02(S4) PXSX(S4) RP03(S4) PXSX(S4) RP04(S4) PXSX(S4) [...] acpitimer0 at acpi0: 3579545 Hz, 32 bits acpimcfg0 at acpi0 addr 0xe0000000, bus 0-255 acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat cpu0 at mainbus0: apid 0 (boot processor) cpu0: Intel(R) Pentium(R) CPU J4205 @ 1.50GHz, 1497.60 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,CX16,xTPR,PDCM,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,RDRAND,NXE,PAGE1GB,RDTSCP,LONG,LAHF,3DNOWP,PERF,ITSC,FSGSBASE,SMEP,ERMS,MPX,RDSEED,SMAP,CLFLUSHOPT,PT,SHA,SENSOR,ARAT cpu0: 1MB 64b/line 16-way L2 cache cpu0: TSC frequency 1497600000 Hz cpu0: smt 0, core 0, package 0 mtrr: Pentium Pro MTRR support, 10 var ranges, 88 fixed ranges cpu0: apic clock running at 19MHz cpu0: mwait min=64, max=64, C-substates=0.2.0.2.4.2.1.1, IBE cpu at mainbus0: not configured cpu at mainbus0: not configured cpu at mainbus0: not configured ioapic0 at mainbus0: apid 1 pa 0xfec00000, version 20, 120 pins acpiprt0 at acpi0: bus 0 (PCI0) acpiprt1 at acpi0: bus 1 (RP03) acpiprt2 at acpi0: bus 2 (RP04) acpiprt3 at acpi0: bus 3 (RP05) acpiprt4 at acpi0: bus 4 (RP06) acpiec0 at acpi0: not present acpicpu0 at acpi0: C3(10@150 mwait.1@0x60), C2(10@50 mwait.1@0x21), C1(1000@1 mwait.1@0x1), PSS acpipwrres0 at acpi0: FN00, resource for FAN0 acpitz0 at acpi0: critical temperature is 100 degC acpibtn0 at acpi0: PWRB "INT3452" at acpi0 not configured "INT3452" at acpi0 not configured "INT3452" at acpi0 not configured "INT3452" at acpi0 not configured "INT33A1" at acpi0 not configured "PNP0C0B" at acpi0 not configured acpivideo0 at acpi0: GFX0 acpivout0 at acpivideo0: DD1F cpu0: Enhanced SpeedStep 1497 MHz: speeds: 1501, 1500, 1400, 1300, 1200, 1100, 1000, 900, 800 MHz pci0 at mainbus0 bus 0 pchb0 at pci0 dev 0 function 0 vendor "Intel", unknown product 0x5af0 rev 0x0b inteldrm0 at pci0 dev 2 function 0 vendor "Intel", unknown product 0x5a84 rev 0x0b drm0 at inteldrm0 inteldrm0: msi error: [drm:pid0:i915_firmware_load_error_print] *ERROR* failed to load firmware i915/bxt_dmc_ver1.bin (-22) error: [drm:pid0:i915_gem_init_hw] *ERROR* Failed to initialize GuC, error -8 (ignored) inteldrm0: 1440x900, 32bpp Unclaimed register detected after writing to register 0x68980 wsdisplay0 at inteldrm0 mux 1: console (std, vt100 emulation) wsdisplay0: screen 1-5 added (std, vt100 emulation) azalia0 at pci0 dev 14 function 0 vendor "Intel", unknown product 0x5a98 rev 0x0b: msi azalia0: codecs: Realtek/0x0892, 0x0000/0x0000, using Realtek/0x0892 audio0 at azalia0 vendor "Intel", unknown product 0x5a9a (class communications subclass miscellaneous, rev 0x0b) at pci0 dev 15 function 0 not configured ahci0 at pci0 dev 18 function 0 vendor "Intel", unknown product 0x5ae3 rev 0x0b: msi, AHCI 1.3.1 ahci0: port 0: 6.0Gb/s ahci0: port 1: 6.0Gb/s scsibus1 at ahci0: 32 targets sd0 at scsibus1 targ 0 lun 0: <ATA, ST2000NM0008-2F3, SN01> SCSI3 0/direct fixed naa.5000c500a20c8afc sd0: 1907729MB, 512 bytes/sector, 3907029168 sectors sd1 at scsibus1 targ 1 lun 0: <ATA, ST2000NM0008-2F3, SN01> SCSI3 0/direct fixed naa.5000c500a20c72e9 sd1: 1907729MB, 512 bytes/sector, 3907029168 sectors ppb0 at pci0 dev 19 function 0 vendor "Intel", unknown product 0x5ad8 rev 0xfb: msi pci1 at ppb0 bus 1 re0 at pci1 dev 0 function 0 "Realtek 8168" rev 0x11: RTL8168G/8111G (0x4c00), msi, address 70:85:c2:4a:bf:5b rgephy0 at re0 phy 7: RTL8251 PHY, rev. 0 ppb1 at pci0 dev 19 function 1 vendor "Intel", unknown product 0x5ad9 rev 0xfb: msi pci2 at ppb1 bus 2 ppb2 at pci0 dev 19 function 2 vendor "Intel", unknown product 0x5ada rev 0xfb: msi pci3 at ppb2 bus 3 ahci1 at pci3 dev 0 function 0 "ASMedia ASM1061 AHCI" rev 0x02: msi, AHCI 1.2 ahci1: port 0: 1.5Gb/s scsibus2 at ahci1: 32 targets cd0 at scsibus2 targ 0 lun 0: <HL-DT-ST, DVDRAM GH15F, EG00> ATAPI 5/cdrom removable ppb3 at pci0 dev 19 function 3 vendor "Intel", unknown product 0x5adb rev 0xfb: msi pci4 at ppb3 bus 4 xhci0 at pci0 dev 21 function 0 vendor "Intel", unknown product 0x5aa8 rev 0x0b: msi 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 pcib0 at pci0 dev 31 function 0 vendor "Intel", unknown product 0x5ae8 rev 0x0b vendor "Intel", unknown product 0x5ad4 (class serial bus subclass SMBus, rev 0x0b) at pci0 dev 31 function 1 not configured isa0 at pcib0 isadma0 at isa0 com0 at isa0 port 0x3f8/8 irq 4: 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 wsdisplay0 pcppi0 at isa0 port 0x61 spkr0 at pcppi0 lpt0 at isa0 port 0x378/4 irq 7 vmm0 at mainbus0: VMX/EPT uhidev0 at uhub0 port 2 configuration 1 interface 0 "Logitech USB Receiver" rev 2.00/12.03 addr 2 uhidev0: iclass 3/1 ukbd0 at uhidev0: 8 variable keys, 6 key codes wskbd1 at ukbd0 mux 1 wskbd1: connecting to wsdisplay0 uhidev1 at uhub0 port 2 configuration 1 interface 1 "Logitech USB Receiver" rev 2.00/12.03 addr 2 uhidev1: iclass 3/1, 8 report ids ums0 at uhidev1 reportid 2: 16 buttons, Z and W dir wsmouse0 at ums0 mux 0 uhid0 at uhidev1 reportid 3: input=4, output=0, feature=0 uhid1 at uhidev1 reportid 4: input=1, output=0, feature=0 uhid2 at uhidev1 reportid 8: input=1, output=0, feature=0 uhidev2 at uhub0 port 2 configuration 1 interface 2 "Logitech USB Receiver" rev 2.00/12.03 addr 2 uhidev2: iclass 3/0, 33 report ids uhid3 at uhidev2 reportid 16: input=6, output=6, feature=0 uhid4 at uhidev2 reportid 17: input=19, output=19, feature=0 uhid5 at uhidev2 reportid 32: input=14, output=14, feature=0 uhid6 at uhidev2 reportid 33: input=31, output=31, feature=0 umass0 at uhub0 port 3 configuration 1 interface 0 "SanDisk Cruzer Fit" rev 2.00/1.27 addr 3 umass0: using SCSI over Bulk-Only scsibus3 at umass0: 2 targets, initiator 0 sd2 at scsibus3 targ 1 lun 0: <SanDisk, Cruzer Fit, 1.27> SCSI4 0/direct removable serial.07815571750317107221 sd2: 15267MB, 512 bytes/sector, 31266816 sectors ulpt0 at uhub0 port 6 configuration 1 interface 1 "EPSON EPSON WorkForce 845 Series" rev 2.00/1.00 addr 4 ulpt0: using bi-directional mode umass1 at uhub0 port 6 configuration 1 interface 2 "EPSON EPSON WorkForce 845 Series" rev 2.00/1.00 addr 4 umass1: using SCSI over Bulk-Only scsibus4 at umass1: 2 targets, initiator 0 sd3 at scsibus4 targ 1 lun 0: <EPSON, Storage, 1.00> SCSI2 0/direct removable serial.04b80892593037353778 ugen0 at uhub0 port 6 configuration 1 "EPSON EPSON WorkForce 845 Series" rev 2.00/1.00 addr 4 vscsi0 at root scsibus5 at vscsi0: 256 targets softraid0 at root scsibus6 at softraid0: 256 targets softraid0: sd4 was not shutdown properly sd4 at scsibus6 targ 1 lun 0: <OPENBSD, SR RAID 1, 006> SCSI2 0/direct fixed sd4: 1907726MB, 512 bytes/sector, 3907023473 sectors root on sd4a (6b2b6733acf1cfed.a) swap on sd4b dump on sd4b WARNING: / was not properly unmounted