[AT&T HTC One (M7)] OCTechs:
I managed to flash a firmware provided by Android Revolution 4.06.1540.2.zip, renamed it to "firmware.zip" and was able to pull that off successfully (I think "see code below") but even after that, I tried to manually flash the rom.zip and install it via the exe and still no profit. :/

< waiting for device >
sending 'zip' (43288 KB)...
OKAY [ 2.976s]
writing 'zip'...
(bootloader) adopting the signature contained in this image...
(bootloader) signature checking...
(bootloader) zip header checking...
(bootloader) zip info parsing...
(bootloader) checking model ID...
(bootloader) checking custom ID...
(bootloader) checking main version...
(bootloader) checking hboot version...
(bootloader) start image[boot] unzipping & flushing...
(bootloader) [RUU]UZ,boot,0
(bootloader) [RUU]UZ,boot,11
(bootloader) [RUU]UZ,boot,24
(bootloader) [RUU]UZ,boot,35
(bootloader) [RUU]UZ,boot,47
(bootloader) [RUU]UZ,boot,59
(bootloader) [RUU]UZ,boot,72
(bootloader) [RUU]UZ,boot,82
(bootloader) [RUU]UZ,boot,93
(bootloader) [RUU]UZ,boot,100
(bootloader) [RUU]WP,boot,0
(bootloader) [RUU]WP,boot,99
(bootloader) [RUU]WP,boot,100
(bootloader) ...... Successful
(bootloader) start image[recovery] unzipping & flushing...
(bootloader) [RUU]UZ,recovery,0
(bootloader) [RUU]UZ,recovery,6
(bootloader) [RUU]UZ,recovery,12
(bootloader) [RUU]UZ,recovery,21
(bootloader) [RUU]UZ,recovery,29
(bootloader) [RUU]UZ,recovery,38
(bootloader) [RUU]UZ,recovery,45
(bootloader) [RUU]UZ,recovery,50
(bootloader) [RUU]UZ,recovery,67
(bootloader) [RUU]UZ,recovery,75
(bootloader) [RUU]UZ,recovery,83
(bootloader) [RUU]UZ,recovery,88
(bootloader) [RUU]UZ,recovery,97
(bootloader) [RUU]UZ,recovery,100
(bootloader) [RUU]WP,recovery,0
(bootloader) [RUU]WP,recovery,99
(bootloader) [RUU]WP,recovery,100
(bootloader) ...... Successful
(bootloader) start image[rpm] unzipping & flushing...
(bootloader) [RUU]UZ,rpm,0
(bootloader) [RUU]UZ,rpm,100
(bootloader) signature checking...
(bootloader) ...... Successful
(bootloader) start image[sbl1-1] unzipping & flushing...
(bootloader) [RUU]UZ,sbl1-1,0
(bootloader) [RUU]UZ,sbl1-1,100
(bootloader) signature checking...
(bootloader) verified fail
(bootloader) ..... Bypassed
(bootloader) start image[sbl1-2] unzipping & flushing...
(bootloader) [RUU]UZ,sbl1-2,0
(bootloader) [RUU]UZ,sbl1-2,100
(bootloader) signature checking...
(bootloader) verified fail
(bootloader) ..... Bypassed
(bootloader) start image[sbl1-3] unzipping & flushing...
(bootloader) [RUU]UZ,sbl1-3,0
(bootloader) [RUU]UZ,sbl1-3,100
(bootloader) signature checking...
(bootloader) ...... Successful
(bootloader) start image[sbl2] unzipping & flushing...
(bootloader) [RUU]UZ,sbl2,0
(bootloader) [RUU]UZ,sbl2,100
(bootloader) signature checking...
(bootloader) ...... Successful
(bootloader) start image[sbl3] unzipping & flushing...
(bootloader) [RUU]UZ,sbl3,0
(bootloader) [RUU]UZ,sbl3,100
(bootloader) signature checking...
(bootloader) ...... Successful
(bootloader) start image[tp] unzipping & flushing...
(bootloader) [RUU]UZ,tp,0
(bootloader) [RUU]UZ,tp,100
(bootloader) ..... Bypassed
(bootloader) start image[tz] unzipping & flushing...
(bootloader) [RUU]UZ,tz,0
(bootloader) [RUU]UZ,tz,100
(bootloader) signature checking...
(bootloader) ...... Successful
(bootloader) start image[radio] unzipping & flushing...
(bootloader) [RUU]UZ,radio,0
(bootloader) [RUU]UZ,radio,6
(bootloader) [RUU]UZ,radio,12
(bootloader) [RUU]UZ,radio,18
(bootloader) [RUU]UZ,radio,24
(bootloader) [RUU]UZ,radio,30
(bootloader) [RUU]UZ,radio,37
(bootloader) [RUU]UZ,radio,43
(bootloader) [RUU]UZ,radio,49
(bootloader) [RUU]UZ,radio,55
(bootloader) [RUU]UZ,radio,62
(bootloader) [RUU]UZ,radio,68
(bootloader) [RUU]UZ,radio,74
(bootloader) [RUU]UZ,radio,81
(bootloader) [RUU]UZ,radio,87
(bootloader) [RUU]UZ,radio,93
(bootloader) [RUU]UZ,radio,99
(bootloader) [RUU]UZ,radio,100
(bootloader) [RUU]WP,radio,0
(bootloader) [RUU]WP,radio,24
(bootloader) [RUU]WP,radio,49
(bootloader) [RUU]WP,radio,74
(bootloader) [RUU]WP,radio,99
(bootloader) [RUU]WP,radio,100
(bootloader) ...... Successful
(bootloader) start image[rcdata] unzipping & flushing...
(bootloader) [RUU]UZ,rcdata,0
(bootloader) [RUU]UZ,rcdata,42949671
(bootloader) [RUU]WP,rcdata,0
(bootloader) [RUU]WP,rcdata,42949671
(bootloader) ...... Successful
OKAY [ 27.115s]
finished. total time: 30.095s

It did however change my GetVar slightly (below):

(bootloader) version: 0.5
(bootloader) version-bootloader: 1.56.0000
(bootloader) version-baseband: 4A.22.3263.14
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main: 4.06.1540.2
(bootloader) version-misc: PVT SHIP S-ON
(bootloader) serialno:
(bootloader) imei:
(bootloader) meid: 00000000000000
(bootloader) product: m7_ul
(bootloader) platform: HBOOT-8064
(bootloader) modelid: PN0712000
(bootloader) cidnum: CWS__001
(bootloader) battery-status: good
(bootloader) battery-voltage: 4276mV
(bootloader) partition-layout: Generic
(bootloader) security: on
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) commitno-bootloader: dirty-bee46337
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0
all: Done!
finished. total time: 0.055s