[Verizon HTC One (M8)] FrickDude:
Thank you! Can't believe that was all :)

C:\...\AppData\Local\Android\sdk\platform-tools>adb reboot bootloader
* daemon not running. starting it now on port 5037 *
* daemon started successfully *

C:\...\AppData\Local\Android\sdk\platform-tools>Fastboot oem rebootRUU
...
(bootloader) Start Verify: 0
OKAY [ 0.020s]
finished. total time: 0.024s

C:\...\AppData\Local\Android\sdk\platform-tools>fastboot flash zip firmware.zip
target reported max download size of 1826418688 bytes
sending 'zip' (29855 KB)...
OKAY [ 2.143s]
writing 'zip'...
(bootloader) zip header checking...
(bootloader) zip info parsing...
(bootloader) checking model ID...
(bootloader) checking custom ID...
(bootloader) start image[hboot] unzipping for pre-update check...
(bootloader) total_image_number=8

(bootloader) start image[hboot] flushing...
(bootloader) [RUU]WP,hboot,0
(bootloader) [RUU]WP,hboot,99
(bootloader) [RUU]WP,hboot,100
(bootloader) ...... Successful
(bootloader) current_image_number=0

(bootloader) start image[sbl1] unzipping for pre-update...
(bootloader) start image[sbl1] flushing...
(bootloader) signature checking...
(bootloader) verified fail
(bootloader) ...... Bypassed
(bootloader) start image[sbl1] unzipping for pre-update...
(bootloader) start image[sbl1] flushing...
(bootloader) signature checking...
(bootloader) [RUU]WP,sbl1,0
(bootloader) [RUU]WP,sbl1,100
(bootloader) ...... Successful
(bootloader) start image[sbl1] unzipping for pre-update...
(bootloader) start image[sbl1] flushing...
(bootloader) signature checking...
(bootloader) verified fail
(bootloader) ...... Bypassed
(bootloader) current_image_number=1

(bootloader) current_image_number=2

(bootloader) current_image_number=3

(bootloader) start image[rpm] unzipping for pre-update...
(bootloader) start image[rpm] flushing...
(bootloader) [RUU]WP,rpm,0
(bootloader) [RUU]WP,rpm,100
(bootloader) ...... Successful
(bootloader) current_image_number=4

(bootloader) start image[tz] unzipping for pre-update...
(bootloader) start image[tz] flushing...
(bootloader) [RUU]WP,tz,0
(bootloader) [RUU]WP,tz,100
(bootloader) ...... Successful
(bootloader) current_image_number=5

(bootloader) current_image_number=6

(bootloader) current_image_number=7

FAILED (remote: 90 hboot pre-update! please flush image again immediately)
finished. total time: 5.263s

C:\...\AppData\Local\Android\sdk\platform-tools>

That's an awful lot of "failed" in all that text. Should I be scared to reboot? I flashed the VZWm8Mfirmwarenobootrecovery.zip file.

Ok I re-ran the flash command and this looks much better.

C:\Users\Jacob\AppData\Local\Android\sdk\platform-tools>fastboot flash zip firmware.zip
target reported max download size of 1826418688 bytes
sending 'zip' (29855 KB)...
OKAY [ 2.248s]
writing 'zip'...
(bootloader) zip header checking...
(bootloader) zip info parsing...
(bootloader) checking model ID...
(bootloader) checking custom ID...
(bootloader) start image[hboot] unzipping for pre-update check...
(bootloader) total_image_number=12

(bootloader) start image[rpm] unzipping & flushing...
(bootloader) [RUU]UZ,rpm,0
(bootloader) [RUU]UZ,rpm,100
(bootloader) [RUU]WP,rpm,0
(bootloader) [RUU]WP,rpm,100
(bootloader) ...... Successful
(bootloader) current_image_number=0

(bootloader) start image[sbl1] unzipping & flushing...
(bootloader) [RUU]UZ,sbl1,0
(bootloader) [RUU]UZ,sbl1,100
(bootloader) signature checking...
(bootloader) verified fail
(bootloader) ..... Bypassed
(bootloader) current_image_number=1

(bootloader) start image[sbl1] unzipping & flushing...
(bootloader) [RUU]UZ,sbl1,0
(bootloader) [RUU]UZ,sbl1,100
(bootloader) signature checking...
(bootloader) [RUU]WP,sbl1,0
(bootloader) [RUU]WP,sbl1,100
(bootloader) ...... Successful
(bootloader) current_image_number=2

(bootloader) start image[sbl1] unzipping & flushing...
(bootloader) [RUU]UZ,sbl1,0
(bootloader) [RUU]UZ,sbl1,100
(bootloader) signature checking...
(bootloader) verified fail
(bootloader) ..... Bypassed
(bootloader) current_image_number=3

(bootloader) start image[sensor_hub] unzipping & flushing...
(bootloader) [RUU]UZ,sensor_hub,0
(bootloader) [RUU]UZ,sensor_hub,100
(bootloader) [RUU]WP,sensor_hub,0
(bootloader) [RUU]WP,sensor_hub,4
(bootloader) [RUU]WP,sensor_hub,8
(bootloader) [RUU]WP,sensor_hub,12
(bootloader) [RUU]WP,sensor_hub,16
(bootloader) [RUU]WP,sensor_hub,20
(bootloader) [RUU]WP,sensor_hub,24
(bootloader) [RUU]WP,sensor_hub,28
(bootloader) [RUU]WP,sensor_hub,32
(bootloader) [RUU]WP,sensor_hub,36
(bootloader) [RUU]WP,sensor_hub,40
(bootloader) [RUU]WP,sensor_hub,44
(bootloader) [RUU]WP,sensor_hub,48
(bootloader) [RUU]WP,sensor_hub,52
(bootloader) [RUU]WP,sensor_hub,56
(bootloader) [RUU]WP,sensor_hub,60
(bootloader) [RUU]WP,sensor_hub,64
(bootloader) [RUU]WP,sensor_hub,68
(bootloader) [RUU]WP,sensor_hub,72
(bootloader) [RUU]WP,sensor_hub,76
(bootloader) [RUU]WP,sensor_hub,80
(bootloader) [RUU]WP,sensor_hub,84
(bootloader) [RUU]WP,sensor_hub,88
(bootloader) [RUU]WP,sensor_hub,92
(bootloader) [RUU]WP,sensor_hub,96
(bootloader) [RUU]WP,sensor_hub,100
(bootloader) ...... Successful
(bootloader) current_image_number=4

(bootloader) start image[sp1] unzipping & flushing...
(bootloader) ...... Successful
(bootloader) current_image_number=5

(bootloader) start image[tz] unzipping & flushing...
(bootloader) ...... Successful
(bootloader) current_image_number=6

(bootloader) start image[wcnss] unzipping & flushing...
(bootloader) ...... Successful
(bootloader) current_image_number=7

(bootloader) start image[adsp] unzipping & flushing...
(bootloader) ...... Successful
(bootloader) current_image_number=8

(bootloader) start image[hboot] unzipping & flushing...
(bootloader) ...... Successful
(bootloader) current_image_number=9

(bootloader) start image[radio] unzipping & flushing...
(bootloader) trying to rename MBA
(bootloader) ...... Successful
(bootloader) current_image_number=10

(bootloader) start image[rcdata] unzipping & flushing...
(bootloader) ...... Successful
(bootloader) current_image_number=11

OKAY [ 57.866s]
finished. total time: 60.120s

C:\Users\Jacob\AppData\Local\Android\sdk\platform-tools>