[Nexus 6 Q&A, Help & Troubleshooting] cohm2010:
Hello! After going through all the Q&A/Help threads regarding "boot loops", I was not able to find a solution that worked for my situation. I'm hoping to to get some advice for how to fix the following issue:

Issue: Nexus 6 (XT1103, 64GB, unlocked boot loader, no root, stock recovery, ROM = last OTA security update) was found boot-looping when I pulled it out of my pocket one afternoon. I can get to boot loader menu (Power + Volume DN), but I cannot enter recovery mode. Choosing any option from the main boot loader menu restarts the boot-loop.

Knowns: Battery was nearly dead, so I originally thought this was the cause. Ordered new battery and installed on Thursday. Still boot-looping after trying to boot to OS.

Things I've already tried:

Battery replacement (OEM EZ30)

Cleared cache from recovery (I was able to get recovery running one time, cleared cache, boot-loop restarted on reboot)

Can access with fastboot from boot loader menu (serial number is correct)

Cannot access with adb due to inability to start recovery (obviously)

Tried flashing TWRP using fastboot and then rebooting to recovery --> boot-loop starts again

Tried flashing 10/2017 factory image using one-by-one method --> boot-loop starts again

"Safe" (?) boot from boot-loader menu by pressing/holding power button when "BOOTLOADER LOGS" is selected --> boot-loop starts again

Tried loading TWRP from laptop using fastboot ("fastboot boot C:\Android\TWRP.img") --> screen changes momentarily, then boot-loop starts again

Erased and flashed cache and userdata using fastboot --> boot-loop starts again after reboot

Probably forgot some of the steps along the way....

Results from "fastboot getvar all" (not sure how to remove auto-smileys):

PS C:\Android> fastboot getvar all

(bootloader) version: 0.5

(bootloader) version-bootloader: moto-apq8084-72.04

(bootloader) product: shamu

(bootloader) board: shamu

(bootloader) secure: yes

(bootloader) hwrev: 0x83A0

(bootloader) radio: 0x6

(bootloader) emmc: 64GB Hynix REV=07 PRV=03 TYPE=57

(bootloader) ram: 3072MB Hynix S8 SDRAM DIE=6Gb

(bootloader) cpu: APQ8084 ES1.1

(bootloader) serialno: ZX1G323VQT

(bootloader) cid: 0x00DE

(bootloader) channelid: 0x00

(bootloader) uid: 64EB4F0111000000000000000000

(bootloader) unlocked: yes

(bootloader) securestate: unlocked

(bootloader) iswarrantyvoid: yes

(bootloader) mot_sst: 3

(bootloader) max-download-size: 536870912

(bootloader) reason: Volume down key pressed

(bootloader) imei:

(bootloader) meid:

(bootloader) date:

(bootloader) sku:

(bootloader) iccid:

(bootloader) cust_md5:

(bootloader) max-sparse-size: 268435456

(bootloader) current-time: "Wed Jan 14 23:25:58 UTC 2015"

(bootloader) ro.build.fingerprint: none

(bootloader) ro.build.version.full: none

(bootloader) ro.build.version.qcom: none

(bootloader) version-baseband: D4.01-9625-05.45+FSG-9625-02.117

(bootloader) kernel.version: none

(bootloader) sdi.git: git=MBM-NG-V72.04-0-gf291c61

(bootloader) sbl1.git: git=MBM-NG-V72.04-0-g60ea7e6

(bootloader) rpm.git: git=MBM-NG-V72.04-0-g18b261e

(bootloader) tz.git: git=MBM-NG-V72.04-0-g921699c

(bootloader) aboot.git: git=MBM-NG-V72.04-0-gb11eacf

(bootloader) partition-type:modem: raw

(bootloader) partition-type:metadata: raw

(bootloader) partition-type:sbl1: raw

(bootloader) partition-type:sdi: raw

(bootloader) partition-type:sec: raw

(bootloader) partition-type:ddr: raw

(bootloader) partition-type:aboot: raw

(bootloader) partition-type:rpm: raw

(bootloader) partition-type:utags: raw

(bootloader) partition-type:tz: raw

(bootloader) partition-type:padA: raw

(bootloader) partition-type:sbl1bak: raw

(bootloader) partition-type:abootBackup: raw

(bootloader) partition-type:rpmBackup: raw

(bootloader) partition-type:utagsBackup: raw

(bootloader) partition-type:tzBackup: raw

(bootloader) partition-type:versions: raw

(bootloader) partition-type:frp: raw

(bootloader) partition-type:mdm1m9kefs1: raw

(bootloader) partition-type:mdm1m9kefs2: raw

(bootloader) partition-type:mdm1m9kefs3: raw

(bootloader) partition-type:padB: raw

(bootloader) partition-type:sp: raw

(bootloader) partition-type:keystore: raw

(bootloader) partition-type:logs: raw

(bootloader) partition-type:persist: raw

(bootloader) partition-type:mdm1hob: raw

(bootloader) partition-type:mdm1dhob: raw

(bootloader) partition-type:cid: raw

(bootloader) partition-type:logo: raw

(bootloader) partition-type:misc: raw

(bootloader) partition-type:padD: raw

(bootloader) partition-type:mdm1m9kefsc: raw

(bootloader) partition-type:ssd: raw

(bootloader) partition-type:recovery: raw

(bootloader) partition-type:kpan: raw

(bootloader) partition-type:boot: raw

(bootloader) partition-type:cache: ext4

(bootloader) partition-type:oem: raw

(bootloader) partition-type:padC: raw

(bootloader) partition-type:system: raw

(bootloader) partition-type:userdata: ext4

(bootloader) partition-size:modem: 0x0000000007000000

(bootloader) partition-size:metadata: 0x0000000001000000

(bootloader) partition-size:sbl1: 0x0000000000060000

(bootloader) partition-size:sdi: 0x000000000000e000

(bootloader) partition-size:sec: 0x0000000000004000

(bootloader) partition-size:ddr: 0x0000000000008000

(bootloader) partition-size:aboot: 0x0000000000100000

(bootloader) partition-size:rpm: 0x0000000000040000

(bootloader) partition-size:utags: 0x0000000000080000

(bootloader) partition-size:tz: 0x000000000007d000

(bootloader) partition-size:padA: 0x000000000040f000

(bootloader) partition-size:sbl1bak: 0x0000000000060000

(bootloader) partition-size:abootBackup: 0x0000000000100000

(bootloader) partition-size:rpmBackup: 0x0000000000040000

(bootloader) partition-size:utagsBackup: 0x0000000000080000

(bootloader) partition-size:tzBackup: 0x000000000007d000

(bootloader) partition-size:versions: 0x0000000000001000

(bootloader) partition-size:frp: 0x0000000000080000

(bootloader) partition-size:mdm1m9kefs1: 0x0000000000100000

(bootloader) partition-size:mdm1m9kefs2: 0x0000000000100000

(bootloader) partition-size:mdm1m9kefs3: 0x0000000000100000

(bootloader) partition-size:padB: 0x0000000000100000

(bootloader) partition-size:sp: 0x0000000001000000

(bootloader) partition-size:keystore: 0x0000000001000000

(bootloader) partition-size:logs: 0x0000000000200000

(bootloader) partition-size:persist: 0x0000000002000000

(bootloader) partition-size:mdm1hob: 0x0000000000040000

(bootloader) partition-size:mdm1dhob: 0x0000000000008000

(bootloader) partition-size:cid: 0x0000000000020000

(bootloader) partition-size:logo: 0x0000000000800000

(bootloader) partition-size:misc: 0x0000000000100000

(bootloader) partition-size:padD: 0x0000000000278000

(bootloader) partition-size:mdm1m9kefsc: 0x0000000000000400

(bootloader) partition-size:ssd: 0x0000000000002000

(bootloader) partition-size:recovery: 0x0000000001004000

(bootloader) partition-size:kpan: 0x00000000008e0000

(bootloader) partition-size:boot: 0x0000000001000000

(bootloader) partition-size:cache: 0x0000000010000000

(bootloader) partition-size:oem: 0x0000000004000000

(bootloader) partition-size:padC: 0x0000000000100000

(bootloader) partition-size:system: 0x0000000080000000

(bootloader) partition-size:userdata: 0x0000000de97e0000

(bootloader) qe:

(bootloader) ro.carrier: unknown

(bootloader) dm-verity-state: Not Supported

all: listed above

Finished. Total time: 0.472s

PS C:\Android>

So far, nothing has worked. Originally, I was hoping to recover my user data as my last backup was a little too long ago (she's been very reliable for the last 3.5 years). At this point, I would be happy to just recover the OS and get the device working again with my brand-new battery.

Does anyone have some good advice for how to troubleshoot and fix this boot-loop issue?

Thanks!