I really would think before trying this in any form of production environment. It did however work for a VMware lab I was building today (05/04/2022). The issue occurred when upgrading esxi from 6.0 to 6.5 by booting to the install media. One machine worked as expected, the other for some unknown reason would only allow a new install, not an upgrade. After a very small amount of research I found this.

Sounds perhaps sketchy, but it is a lab so… Checking bootbank:

root@labby:~] ls /bootbank/
a.b00         ehci_ehc.v00  ipmi_ipm.v02  misc_cni.v00  net_mlx4.v00  s.v00         scsi_bnx.v00  scsi_qla.v00  vsanheal.v00
ata_pata.v00  elxnet.v00    jumpstrt.gz   misc_dri.v00  net_mlx4.v01  sata_ahc.v00  scsi_bnx.v01  scsi_qla.v01  vsanmgmt.v00
ata_pata.v01  emulex_c.v00  k.b00         mtip32xx.v00  net_nx_n.v00  sata_ata.v00  scsi_fni.v00  state.tgz     weaselin.t00
ata_pata.v02  emulex_e.v00  lpfc.v00      net_bnx2.v00  net_tg3.v00   sata_sat.v00  scsi_hps.v00  svscimpr.v00  xhci_xhc.v00
ata_pata.v03  esx_dvfi.v00  lsi_mr3.v00   net_bnx2.v01  net_vmxn.v00  sata_sat.v01  scsi_ips.v00  tboot.b00     xorg.v00
ata_pata.v04  esx_ui.v00    lsi_msgp.v00  net_cnic.v00  nmlx4_co.v00  sata_sat.v02  scsi_lpf.v00  uc_amd.b00
ata_pata.v05  fujitsu_.v00  lsiprovi.v00  net_e100.v00  nmlx4_en.v00  sata_sat.v03  scsi_meg.v00  uc_intel.b00
ata_pata.v06  fujitsu_.v01  lsu_hp_h.v00  net_e100.v01  nmlx4_rd.v00  sata_sat.v04  scsi_meg.v01  uhci_usb.v00
ata_pata.v07  ima_be2i.v00  lsu_lsi_.v00  net_enic.v00  nvme.v00      sb.v00        scsi_meg.v02  user.b00
b.b00         ima_qla4.v00  lsu_lsi_.v01  net_forc.v00  ohci_usb.v00  scsi_aac.v00  scsi_mpt.v00  useropts.gz
block_cc.v00  imgdb.tgz     lsu_lsi_.v02  net_i40e.v00  qlnative.v00  scsi_adp.v00  scsi_mpt.v01  vmware_e.v00
boot.cfg      ipmi_ipm.v00  lsu_lsi_.v03  net_igb.v00   qlogic_a.v00  scsi_aic.v00  scsi_mpt.v02  vmware_f.v00
chardevs.b00  ipmi_ipm.v01  lsu_lsi_.v04  net_ixgb.v00  rste.v00      scsi_be2.v00  scsi_mpt.v03  vsan.v00

There are indeed files in there. Next check altbootbank

[root@labby:~] ls /altbootbank/

Not many files in there. So lets copy some over:

[root@labby:~] cp /bootbank/* /altbootbank/

Next lets reboot and try the upgrade again:


Really! I must admin I wasn’t expecting that to work.