[HTC U12+ Questions & Answers] Tiltdozer:
I get this when in RUU.

PS C:\adb> fastboot oem rebootRUU

...

OKAY [ 0.001s]

finished. total time: 0.001s

htc_fastboot finished. total time: 1.457s

PS C:\adb> fastboot flash zip 2Q55IMG.zip

htc_fastboot v3.0.9.2 (2015-05-29)

target rom version: 1.30.401.2

found large-zip header, file count: 27

processing file 1/27...

sending 'zip' (92209 KB)...

OKAY [ 3.876s]

writing 'zip'...

(bootloader) HOSD CL#1050003

(bootloader) [multislot] gpt_main_64g_sda.img found, Will force to switc

(bootloader) h slot to _a

(bootloader) Current slot: _b, check gpt_main* only

(bootloader) update GPT (gpt_main_64g_sda.img) successfully.

(bootloader) [multislot] Set bootlun to _a OK

(bootloader) update GPT (gpt_main_64g_sdb.img) successfully.

(bootloader) update GPT (gpt_main_64g_sdc.img) successfully.

(bootloader) update GPT (gpt_main_64g_sdd.img) successfully.

(bootloader) update GPT (gpt_main_64g_sde.img) successfully.

(bootloader) update GPT (gpt_main_64g_sdf.img) successfully.

(bootloader) Perform pre-update

(bootloader) WARN Skip backup_android-info.txt due to unmatched partitio

(bootloader) n name

(bootloader) get 49 images from zip(zip_type=3)

(bootloader) start@49

(bootloader) cota.img@BYPASS

(bootloader) xbl-sdm845-1.img_a@100%

(bootloader) xbl-sdm845-1.img_b@100%

(bootloader) xbl_config-sdm845-1.img_a@100%

(bootloader) xbl_config-sdm845-1.img_b@100%

(bootloader) hosd_signed.img_a@100%

(bootloader) hosd_signed.img_b@100%

(bootloader) apdp-sdm845-1.img@BYPASS

(bootloader) abl_signed.img_a@100%

(bootloader) abl_signed.img_b@100%

(bootloader) aop-sdm845-1.img_a@100%

(bootloader) aop-sdm845-1.img_b@100%

(bootloader) pmic-sdm845-1.img_a@100%

(bootloader) pmic-sdm845-1.img_b@100%

(bootloader) boot_signed.img_a@BYPASS

(bootloader) boot_signed.img_b@BYPASS

(bootloader) dtbo.img_a@100%

(bootloader) dtbo.img_b@100%

(bootloader) vbmeta.img_a@100%

(bootloader) vbmeta.img_b@100%

(bootloader) qupfw.img_a@100%

(bootloader) qupfw.img_b@100%

(bootloader) dsp.img_a@BYPASS

(bootloader) dsp.img_b@BYPASS

(bootloader) tz-sdm845-1.img_a@100%

(bootloader) tz-sdm845-1.img_b@100%

(bootloader) hyp-sdm845-1.img_a@100%

(bootloader) hyp-sdm845-1.img_b@100%

(bootloader) devcfg-sdm845-1.img_a@100%

(bootloader) devcfg-sdm845-1.img_b@100%

(bootloader) cmnlib-sdm845-1.img_a@100%

(bootloader) cmnlib-sdm845-1.img_b@100%

(bootloader) cmnlib64-sdm845-1.img_a@100%

(bootloader) cmnlib64-sdm845-1.img_b@100%

(bootloader) keymaster-sdm845-1.img_a@100%

(bootloader) keymaster-sdm845-1.img_b@100%

(bootloader) lockbooter.img_a@100%

(bootloader) lockbooter.img_b@100%

(bootloader) hvbmeta.img@100%

(bootloader) splash1.nb0@BYPASS

(bootloader) bluetooth.img_a@BYPASS

(bootloader) bluetooth.img_b@BYPASS

(bootloader) edge_update.img@BYPASS

(bootloader) edge_update_convex.img@BYPASS

(bootloader) edge_update_flat.img@BYPASS

(bootloader) edge_update_concave.img@BYPASS

(bootloader) edge_update_newconvex.img@BYPASS

(bootloader) radio.img_a@BYPASS

(bootloader) radio.img_b@BYPASS

FAILED (remote: 90 hboot pre-update! please flush image again immediately )

finished. total time: 6.602s

preupdate done, rebooting...

resending command...

sending 'zip' (92209 KB)...

OKAY [ 4.148s]

writing 'zip'...

(bootloader) ERR lzipv2_init : Cannot open file /dev/fastboot_download_c

(bootloader) der

(bootloader) ERR [SD_UPDATE_ERR] sddownload failed: 22

(bootloader) ERR ZIP ERROR, exit read zip loop

(bootloader) Update zip file OK

(bootloader) end@Done

FAILED (remote: 22 RU_HEADER_ERROR )

finished. total time: 7.183s

htc_fastboot finished. total time: 24.720s