Offline CPU threads

Two of my cpu threads are offline. Any ideas as to why or how to fix it?
tried a live ubuntu usb and all cpu threads are online.

a similar topic(link bellow) solved by enabling smt, but that does not look like the case here.
https://forums.opensuse.org/t/cpus-are-offline/152120

lscpu output:

Architecture:             x86_64
  CPU op-mode(s):         32-bit, 64-bit
  Address sizes:          48 bits physical, 48 bits virtual
  Byte Order:             Little Endian
CPU(s):                   24
  On-line CPU(s) list:    0-5,7-17,19-23
  Off-line CPU(s) list:   6,18
Vendor ID:                AuthenticAMD
  Model name:             AMD Ryzen 9 5900X 12-Core Processor
    CPU family:           25
    Model:                33
    Thread(s) per core:   2
    Core(s) per socket:   11
    Socket(s):            1
    Stepping:             2
    Frequency boost:      enabled
    CPU(s) scaling MHz:   45%
    CPU max MHz:          4950.1948
    CPU min MHz:          0.0000
    BogoMIPS:             7402.24
    Flags:                fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology nonstop_tsc cpuid extd_apicid aperfmperf rapl p
                          ni pclmulqdq monitor ssse3 fma cx16 sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt tce topoext perfctr_core perfctr_nb
                          bpext perfctr_llc mwaitx cpb cat_l3 cdp_l3 hw_pstate ssbd mba ibrs ibpb stibp vmmcall fsgsbase bmi1 avx2 smep bmi2 erms invpcid cqm rdt_a rdseed adx smap clflushopt clwb sha_ni xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc
                          cqm_mbm_total cqm_mbm_local user_shstk clzero irperf xsaveerptr rdpru wbnoinvd arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold avic v_vmsave_vmload vgif v_spec_ctrl umip pku
                          ospke vaes vpclmulqdq rdpid overflow_recov succor smca fsrm debug_swap
Virtualization features:
  Virtualization:         AMD-V
Caches (sum of all):
  L1d:                    352 KiB (11 instances)
  L1i:                    352 KiB (11 instances)
  L2:                     5.5 MiB (11 instances)
  L3:                     64 MiB (2 instances)
NUMA:
  NUMA node(s):           1
  NUMA node0 CPU(s):      0-5,7-17,19-23
Vulnerabilities:
  Gather data sampling:   Not affected
  Itlb multihit:          Not affected
  L1tf:                   Not affected
  Mds:                    Not affected
  Meltdown:               Not affected
  Mmio stale data:        Not affected
  Reg file data sampling: Not affected
  Retbleed:               Not affected
  Spec rstack overflow:   Mitigation; Safe RET
  Spec store bypass:      Mitigation; Speculative Store Bypass disabled via prctl
  Spectre v1:             Mitigation; usercopy/swapgs barriers and __user pointer sanitization
  Spectre v2:             Mitigation; Retpolines; IBPB conditional; IBRS_FW; STIBP always-on; RSB filling; PBRSB-eIBRS Not affected; BHI Not affected
  Srbds:                  Not affected
  Tsx async abort:        Not affected

Journalctl output:

Jan 07 13:48:31 localhost kernel: CPU6 failed to report alive state
Jan 07 13:48:31 localhost kernel: CPU18 failed to report alive state
Jan 07 16:48:36 localhost (udev-worker)[834]: event12: Failed to call EVIOCSKEYCODE with scan code 0x7c, and key code 190: Invalid argument
Jan 07 16:48:46 localhost (udev-worker)[894]: cpu18: /usr/lib/udev/rules.d/80-hotplug-cpu-mem.rules:10 Failed to write ATTR{/sys/devices/system/cpu/cpu18/online}="1", ignoring: Input/output error
Jan 07 16:48:46 localhost kernel: CPU18 failed to report alive state
Jan 07 16:48:46 localhost kernel:
Jan 07 16:48:56 localhost (udev-worker)[866]: cpu6: /usr/lib/udev/rules.d/80-hotplug-cpu-mem.rules:10 Failed to write ATTR{/sys/devices/system/cpu/cpu6/online}="1", ignoring: Input/output error
Jan 07 16:48:56 localhost kernel: CPU6 failed to report alive state

Too old BIOS?

Post

inxi -aFz

there is a newer version, I’ll try updating later

Machine:
  Type: Desktop System: ASUS product: N/A v: N/A serial: <superuser required>
  Mobo: ASUSTeK model: TUF GAMING B550M-PLUS v: Rev X.0x
    serial: <superuser required> part-nu: SKU uuid: <superuser required>
    UEFI: American Megatrends v: 3607 date: 03/22/2024

While updating the bios to version 3611 the screen went dark and the system remained unresponsive for some time. rebooted and it didn’t post. I reverted back to version 3607

While BIOS updating you have to wait to complete process.
If you broke BIOS update then everything is possible.

Update BIOS. Wait to the end of process. Boot into BIOS - it can take some minutes for the 1st run. Load system default settings. Save. Reboot.

Before running the USB BIOS Flashback tool, please rename the BIOS file (TGB550MP.CAP) using BIOSRenamer."