ChromeOS version: 67.0.3396.101 (the customer has reported CrOS 68 as well)
ChromeOS device model: Google_Snappy.9042.195.0 (HP Chromebook G5 )
Case#: 17010119
User info:https://drive.google.com/open?id=1du8-VbaKcTGHPK0YdGLFgcFbSRvfOdNZkkFRshjKZpo

> Per customer, a large number of their Chromebooks are stuck on the 'Chrome OS is missing or Damaged' screen 
> Recovery Reason: 0x5b No bootable kernel found on disk.
- Timeframe when issue started: About a week ago 

Steps to reproduce: The problem occurs randomly.

Current Behavior / Reproduction: Chromebooks stuck on 'Chrome OS is missing or Damaged' screen.

|======Troubleshooting and Workaround======| 
- Troubleshooting steps taken: 
> Proceed with wipe > no go 
> Proceed with Chromebook Recovery > per customer, Chromebook Recovery via USB sometimes resolves the issue for some time but then will persist again.
> Asked customer to do the following sequence 21 times: 
Turn the device on. 
Leave the device for 20 seconds. 
Turn the device off 

- Existing Workaround: Proceed with Chromebook Recovery several times. 

Drive link to logs: 
https://drive.google.com/open?id=1-YXrmNUvpUj7rdekqA4fCjoVJxBuMTDY

similar error messages we found.
From Message log.
2018-09-24T19:12:21.734589+00:00 ERR kernel: [    2.011432] EXT4-fs (dm-0): couldn't mount as ext3 due to feature incompatibilities
2018-09-24T19:12:21.734590+00:00 INFO kernel: [    2.012000] EXT4-fs (dm-0): mounting ext2 file system using the ext4 subsystem
2018-09-24T19:12:21.734590+00:00 INFO kernel: [    2.016360] EXT4-fs (dm-0): mounted filesystem without journal. Opts: (null)

From event log.
261 | 2018-09-24 12:05:52 | Chrome OS Recovery Mode | No bootable kernel found on disk | 0x5b
262 | 2018-09-24 12:05:52 | Memory Cache Update | Variable | Success
263 | 2018-09-24 12:08:56 | System boot | 145
264 | 2018-09-24 12:08:56 | Chrome OS Recovery Mode | No bootable kernel found on disk | 0x5b

Other suspicious messages from log.(There is not events between 2018-09-24 1:30-2:30 CST, but I found another suspicious messages.)

2018-09-24T19:13:13.336808+00:00 WARNING kernel: [   65.855683] ------------[ cut here ]------------
2018-09-24T19:13:13.336832+00:00 WARNING kernel: [   65.855713] WARNING: CPU: 1 PID: 1108 at ../../../../../tmp/portage/sys-kernel/chromeos-kernel-4_4-4.4.127-r1484/work/chromeos-kernel-4_4-4.4.127/net/wireless/util.c:1143 cfg80211_calculate_bitrate+0xe0/0x195 [cfg80211]
2018-09-24T19:13:13.336834+00:00 WARNING kernel: [   65.855716] Modules linked in: cmac rfcomm uinput iwlmvm snd_soc_sst_bxt_da7219_max98357a snd_soc_hdac_hdmi snd_soc_dmic snd_soc_skl_ssp_clk btusb btrtl btbcm btintel bluetooth uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core iwlwifi iwl7000_mac80211 snd_soc_skl snd_soc_skl_ipc snd_soc_sst_ipc snd_soc_sst_dsp snd_soc_sst_match snd_hda_ext_core snd_hda_core zram acpi_als snd_soc_max98357a snd_soc_da7219 bridge stp llc ipt_MASQUERADE nf_nat_masquerade_ipv4 xt_mark fuse snd_seq_dummy snd_seq snd_seq_device cfg80211 ip6table_filter cros_ec_sensors_ring cros_ec_sensors_core kfifo_buf industrialio joydev
2018-09-24T19:13:13.336835+00:00 WARNING kernel: [   65.855795] CPU: 1 PID: 1108 Comm: shill Tainted: G        W       4.4.127-13890-g6c206f1711d4 #1
2018-09-24T19:13:13.336836+00:00 WARNING kernel: [   65.855798] Hardware name: HP Snappy/Snappy, BIOS Google_Snappy.9042.195.0 04/17/2018
2018-09-24T19:13:13.336837+00:00 WARNING kernel: [   65.855802]  ffffffffc03ee46d 6ecde1edf2d67172 ffff880174c53748 ffffffff85edd7b9
2018-09-24T19:13:13.336838+00:00 WARNING kernel: [   65.855809]  ffff880174c53780 ffffffff85edd76e 6ecde1edf2d67172 0000000000000000
2018-09-24T19:13:13.336839+00:00 WARNING kernel: [   65.855815]  0000000000000282 6ecde1edf2d67172 0000000000000000 ffff880174c537c0
2018-09-24T19:13:13.336839+00:00 WARNING kernel: [   65.855822] Call Trace:
2018-09-24T19:13:13.336840+00:00 WARNING kernel: [   65.855832]  [<ffffffff85edd7b9>] __dump_stack+0x19/0x1b
2018-09-24T19:13:13.336841+00:00 WARNING kernel: [   65.855836]  [<ffffffff85edd76e>] dump_stack+0x4f/0x81
2018-09-24T19:13:13.336842+00:00 WARNING kernel: [   65.855841]  [<ffffffff85c6ce9b>] __warn+0xba/0xf1
2018-09-24T19:13:13.336843+00:00 WARNING kernel: [   65.855845]  [<ffffffff85c6cff9>] warn_slowpath_null+0x38/0x3d
2018-09-24T19:13:13.336843+00:00 WARNING kernel: [   65.855856]  [<ffffffffc03b08f3>] cfg80211_calculate_bitrate+0xe0/0x195 [cfg80211]
2018-09-24T19:13:13.336844+00:00 WARNING kernel: [   65.855868]  [<ffffffffc03bf1ef>] nl80211_put_sta_rate+0x31/0x13a [cfg80211]
2018-09-24T19:13:13.336845+00:00 WARNING kernel: [   65.855879]  [<ffffffffc03bc3a8>] nl80211_send_station+0x2bc/0x73b [cfg80211]
2018-09-24T19:13:13.336846+00:00 WARNING kernel: [   65.855884]  [<ffffffff85d845d4>] ? ksize+0x15/0x8e
2018-09-24T19:13:13.336846+00:00 WARNING kernel: [   65.855896]  [<ffffffffc03c1812>] nl80211_get_station+0x162/0x1be [cfg80211]
2018-09-24T19:13:13.336847+00:00 WARNING kernel: [   65.855905]  [<ffffffff862b7d7c>] genl_rcv_msg+0x32c/0x3cb
2018-09-24T19:13:13.336848+00:00 WARNING kernel: [   65.855909]  [<ffffffff862b7a50>] ? genl_unbind+0x81/0x81
2018-09-24T19:13:13.336848+00:00 WARNING kernel: [   65.855913]  [<ffffffff862b4cd4>] netlink_rcv_skb+0x47/0x95
2018-09-24T19:13:13.336849+00:00 WARNING kernel: [   65.855916]  [<ffffffff862b790a>] genl_rcv+0x28/0x37
2018-09-24T19:13:13.336850+00:00 WARNING kernel: [   65.855919]  [<ffffffff862b38da>] netlink_unicast+0x146/0x1ae
2018-09-24T19:13:13.336851+00:00 WARNING kernel: [   65.855923]  [<ffffffff862b6074>] netlink_sendmsg+0x2ce/0x300
2018-09-24T19:13:13.336851+00:00 WARNING kernel: [   65.855928]  [<ffffffff863781ce>] sock_sendmsg_nosec+0x18/0x25
2018-09-24T19:13:13.336852+00:00 WARNING kernel: [   65.855932]  [<ffffffff86378528>] SyS_sendto+0x114/0x180
2018-09-24T19:13:13.336853+00:00 WARNING kernel: [   65.855936]  [<ffffffff86378fe2>] ? SyS_recvmsg+0x72/0xc5
2018-09-24T19:13:13.336854+00:00 WARNING kernel: [   65.855941]  [<ffffffff8639c9d3>] entry_SYSCALL_64_fastpath+0x27/0x9b
2018-09-24T19:13:13.336855+00:00 WARNING kernel: [   65.855945] ---[ end trace d0d7768f1716eadd ]---


It looks like very similar as  crbug.com/871967 , but it is “ after AUed from M68 -> M69”
The customer is mainly using CrOS67, they have configured AU, but pinned M68, not M69.