[Google Pixel 3 Questions & Answers] Sohcahtoa82:
My Pixel 3's battery was starting to swell up, so I bought a new one from ifixit. Installation was pretty easy, but when I got the new battery in and powered on, it went into Fastboot mode. Here's what I see:

Product revs: blueline MP1.0(ROW)
Bootloader version: b1c1-0.3-6863019
Baseband Revision: g845-00146-201008-B-6891496
Serial number: [redacted]
Secure-Boot: PRODUCTION
NOS-production: error
DRAM: 4Gb Micron LPDDR4X
UFS: 128GB Micron
Device-State: error!
Boot-slot: a
Enter Reason: failed to load/verify boot images

Using the Fastboot menu to reboot into either Rescue or Recovery brings me right back to the Fastboot menu.

I dabble in Android development, and so I already have the Android SDK and it's up to date.

Here's the output of all the things I've tried:

fastboot.exe flash bootloader bootloader-blueline-b1c1-0.3-6863019.img
Sending 'bootloader_a' (8517 KB) OKAY [ 0.299s]
Writing 'bootloader_a' FAILED (remote: 'error getting device locked state No Response')
fastboot: error: Command failed

fastboot flashing unlock
FAILED (remote: 'Error getting device locked state No Response')
fastboot: error: Command failed

fastboot flash radio radio-blueline-g845-00146-201008-b-6891496.img
Sending 'radio_a' (71452 KB) OKAY [ 1.809s]
Writing 'radio_a' FAILED (remote: 'error getting device locked state No Response')
fastboot: error: Command failed

fastboot flashing unlock_critical
FAILED (remote: 'Invalid argument unlock_critical')
fastboot: error: Command failed

fastboot wipe-super
Sending 'system_a' (264 KB) OKAY [ 0.118s]
Writing 'system_a' FAILED (remote: 'error getting device locked state No Response')
fastboot: error: Command failed

fastboot boot .\twrp-3.3.0-0-blueline.img
Sending 'boot.img' (65536 KB) OKAY [ 1.604s]
Booting FAILED (remote: 'error getting device locked state No Response')
fastboot: error: Command failed

fastboot update image-blueline-rq1a.210105.003.zip
--------------------------------------------
Bootloader Version...: b1c1-0.3-6863019
Baseband Version.....: g845-00146-201008-B-6891496
Serial Number........: [redacted]
--------------------------------------------
extracting android-info.txt (0 MB) to RAM...
Checking 'product' OKAY [ 0.059s]
Checking 'version-bootloader' OKAY [ 0.059s]
Checking 'version-baseband' OKAY [ 0.057s]
Setting current slot to 'a' FAILED (remote: 'error getting device locked state No Response')
fastboot: error: Command failed

Here's the output of fastboot getvar all:

C:\Users\DJ\AppData\Local\Android\Sdk\platform-tools>fastboot getvar all
(bootloader) product:blueline
(bootloader) serialno:[redacted]
(bootloader) variant:SDM UFS
(bootloader) max-download-size:0x10000000
(bootloader) slot-suffixes:_a,_b
(bootloader) version-bootloader:b1c1-0.3-6863019
(bootloader) version-baseband:g845-00146-201008-B-6891496
(bootloader) secure-boot:PRODUCTION
(bootloader) secure:yes
(bootloader) hw-revision:MP1.0
(bootloader) is-userspace:no
(bootloader) slot-count:2
(bootloader) current-slot:a
(bootloader) unlocked:error
(bootloader) nos-production:error
(bootloader) off-mode-charge:1
(bootloader) slot-retry-count:a:0
(bootloader) slot-unbootable:a:no
(bootloader) slot-successful:a:yes
(bootloader) slot-retry-count:b:0
(bootloader) slot-unbootable:b:no
(bootloader) slot-successful:b:yes
(bootloader) battery-voltage:4377
(bootloader) battery-soc-ok:yes
(bootloader) snapshot-update-status:none
(bootloader) storage-vendor:MICRON
(bootloader) storage-model:128GB-UFS-MT
(bootloader) storage-rev:9QSN
(bootloader) citadel-fw:error
(bootloader) auto-shutdown:0
(bootloader) partition-type:ssd:raw
(bootloader) partition-size:ssd:0x2000
(bootloader) partition-type:misc:raw
(bootloader) partition-size:misc:0x100000
(bootloader) partition-type:keystore:raw
(bootloader) partition-size:keystore:0x80000
(bootloader) partition-type:frp:raw
(bootloader) partition-size:frp:0x80000
(bootloader) partition-type:system_a:raw
(bootloader) partition-size:system_a:0xB0000000
(bootloader) partition-type:system_b:raw
(bootloader) partition-size:system_b:0xB0000000
(bootloader) partition-type:product_a:raw
(bootloader) partition-size:product_a:0x12C00000
(bootloader) partition-type:product_b:raw
(bootloader) partition-size:product_b:0x12C00000
(bootloader) partition-type:vendor_a:raw
(bootloader) partition-size:vendor_a:0x30000000
(bootloader) partition-type:vendor_b:raw
(bootloader) partition-size:vendor_b:0x30000000
(bootloader) partition-type:boot_a:raw
(bootloader) partition-size:boot_a:0x4000000
(bootloader) partition-type:boot_b:raw
(bootloader) partition-size:boot_b:0x4000000
(bootloader) partition-type:modem_a:raw
(bootloader) partition-size:modem_a:0x5000000
(bootloader) partition-type:modem_b:raw
(bootloader) partition-size:modem_b:0x5000000
(bootloader) partition-type:apdp_a:raw
(bootloader) partition-size:apdp_a:0x40000
(bootloader) partition-type:apdp_b:raw
(bootloader) partition-size:apdp_b:0x40000
(bootloader) partition-type:msadp_a:raw
(bootloader) partition-size:msadp_a:0x40000
(bootloader) partition-type:msadp_b:raw
(bootloader) partition-size:msadp_b:0x40000
(bootloader) partition-type:klog:raw
(bootloader) partition-size:klog:0x400000
(bootloader) partition-type:metadata:raw
(bootloader) partition-size:metadata:0x1000000
(bootloader) partition-type:userdata:raw
(bootloader) partition-size:userdata:0x1BCA7FB000
(bootloader) partition-type:xbl_a:raw
(bootloader) partition-size:xbl_a:0x380000
(bootloader) partition-type:xbl_config_a:raw
(bootloader) partition-size:xbl_config_a:0x20000
(bootloader) partition-type:xbl_b:raw
(bootloader) partition-size:xbl_b:0x380000
(bootloader) partition-type:xbl_config_b:raw
(bootloader) partition-size:xbl_config_b:0x20000
(bootloader) partition-type:ALIGN_TO_128K_1:raw
(bootloader) partition-size:ALIGN_TO_128K_1:0x1A000
(bootloader) partition-type:cdt:raw
(bootloader) partition-size:cdt:0x20000
(bootloader) partition-type:ddr:raw
(bootloader) partition-size:ddr:0x100000
(bootloader) partition-type:modemcal:raw
(bootloader) partition-size:modemcal:0x200000
(bootloader) partition-type:uefivar:raw
(bootloader) partition-size:uefivar:0x100000
(bootloader) partition-type:sec:raw
(bootloader) partition-size:sec:0x4000
(bootloader) partition-type:aop_a:raw
(bootloader) partition-size:aop_a:0x80000
(bootloader) partition-type:tz_a:raw
(bootloader) partition-size:tz_a:0x200000
(bootloader) partition-type:hyp_a:raw
(bootloader) partition-size:hyp_a:0x80000
(bootloader) partition-type:abl_a:raw
(bootloader) partition-size:abl_a:0x200000
(bootloader) partition-type:keymaster_a:raw
(bootloader) partition-size:keymaster_a:0x80000
(bootloader) partition-type:cmnlib_a:raw
(bootloader) partition-size:cmnlib_a:0x80000
(bootloader) partition-type:cmnlib64_a:raw
(bootloader) partition-size:cmnlib64_a:0x80000
(bootloader) partition-type:devcfg_a:raw
(bootloader) partition-size:devcfg_a:0x20000
(bootloader) partition-type:qupfw_a:raw
(bootloader) partition-size:qupfw_a:0x10000
(bootloader) partition-type:vbmeta_a:raw
(bootloader) partition-size:vbmeta_a:0x10000
(bootloader) partition-type:dtbo_a:raw
(bootloader) partition-size:dtbo_a:0x800000
(bootloader) partition-type:storsec_a:raw
(bootloader) partition-size:storsec_a:0x20000
(bootloader) partition-type:aop_b:raw
(bootloader) partition-size:aop_b:0x80000
(bootloader) partition-type:tz_b:raw
(bootloader) partition-size:tz_b:0x200000
(bootloader) partition-type:hyp_b:raw
(bootloader) partition-size:hyp_b:0x80000
(bootloader) partition-type:abl_b:raw
(bootloader) partition-size:abl_b:0x200000
(bootloader) partition-type:keymaster_b:raw
(bootloader) partition-size:keymaster_b:0x80000
(bootloader) partition-type:cmnlib_b:raw
(bootloader) partition-size:cmnlib_b:0x80000
(bootloader) partition-type:cmnlib64_b:raw
(bootloader) partition-size:cmnlib64_b:0x80000
(bootloader) partition-type:devcfg_b:raw
(bootloader) partition-size:devcfg_b:0x20000
(bootloader) partition-type:qupfw_b:raw
(bootloader) partition-size:qupfw_b:0x10000
(bootloader) partition-type:vbmeta_b:raw
(bootloader) partition-size:vbmeta_b:0x10000
(bootloader) partition-type:dtbo_b:raw
(bootloader) partition-size:dtbo_b:0x800000
(bootloader) partition-type:storsec_b:raw
(bootloader) partition-size:storsec_b:0x20000
(bootloader) partition-type:ALIGN_TO_128K_2:raw
(bootloader) partition-size:ALIGN_TO_128K_2:0x1A000
(bootloader) partition-type:persist:raw
(bootloader) partition-size:persist:0x2800000
(bootloader) partition-type:modemst1:raw
(bootloader) partition-size:modemst1:0x200000
(bootloader) partition-type:modemst2:raw
(bootloader) partition-size:modemst2:0x200000
(bootloader) partition-type:fsg:raw
(bootloader) partition-size:fsg:0x200000
(bootloader) partition-type:fsc:raw
(bootloader) partition-size:fsc:0x20000
(bootloader) partition-type:devinfo:raw
(bootloader) partition-size:devinfo:0x1000
(bootloader) partition-type:dip:raw
(bootloader) partition-size:dip:0x100000
(bootloader) partition-type:spunvm:raw
(bootloader) partition-size:spunvm:0x800000
(bootloader) partition-type:limits:raw
(bootloader) partition-size:limits:0x1000
(bootloader) partition-type:toolsfv:raw
(bootloader) partition-size:toolsfv:0x100000
(bootloader) partition-type:logfs:raw
(bootloader) partition-size:logfs:0x800000
(bootloader) partition-type:sti:raw
(bootloader) partition-size:sti:0x200000
(bootloader) partition-type:ImageFv:raw
(bootloader) partition-size:ImageFv:0x200000
(bootloader) partition-type:splash:raw
(bootloader) partition-size:splash:0x4000
all:
Finished. Total time: 9.252s

I've spent at least 4 hours on this, combing through at least a dozen threads here and on reddit, searching Google for people who have had similar problems, but haven't found a solution that works for me. Everything is getting me the error getting device locked state No Response. Doing any of the flash commands and trying slot b or all slots hasn't changed anything. Same error when it tries to set the slot.

I found one thread where someone let their battery drain on the Fastboot menu, then plugged back in and charged and it worked. I tried that and no dice.

I also tried swapping back to the old battery just to try it (obviously not a permanent solution since the old battery is a spicy pillow), and still dead.

At this point, I'm fairly sure the phone is bricked, but I'm praying someone knows something else for me to try. If I can't get this fixed by Sunday, then I guess my next question is...Galaxy S20 or Pixel 5 for my Google Fi?