[Samsung Galaxy S8+ Questions & Answers] ap7x942:
The error message reads "An error has occured while updating the device software. Use the emergency recovery function in the smart switch pc software."

Im picking up from a lot of you by reading various threads that this is no longer an option.

Backstory: This phone was given to me and from day 1 all the system apps would crash to the point where android would reboot. The phone wouldnt shut off completely like it was losing power, but it would go back to the second screen you see on boot. At this point, the settings reported the software build number as being G955USQS5CRI4, which i dont fully understand. Because on the back side of the phone, the model number reads SM-G955U1.

In an attempt to resolve this issue, i used odin and flashed various builds of g955u1 across a few versions of odin and even attempted some g955u builds. At some point during all of this, download mode switched from normal looking download mode to displaying a big ! in a triangle on the screen. None of the usual information youd see is displayed. However, odin still connects and it appears as though i can still flash. I fear i may have made a mistake.

This log is my latest attempt using SM-G955U1_1_20190709124427_xh7461wrxv_fac pulled from SamFirm. G955U1UES6DSG1 either XAA or VZW, i cant remember which.

<ID:0/008> Added!!
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/008> Odin engine v(ID:3.1301)..
<ID:0/008> File analysis..
<ID:0/008> Total Binary size: 5808 M
<ID:0/008> SetupConnection..
<ID:0/008> Initialzation..
<ID:0/008> Set PIT file..
<ID:0/008> DO NOT TURN OFF TARGET!!
<ID:0/008> Get PIT for mapping..
<ID:0/008> Firmware update start..
<ID:0/008> NAND Write Start!!
<ID:0/008> SingleDownload.
<ID:0/008> abl.elf
<ID:0/008> bksecapp.mbn
<ID:0/008> xbl.elf
<ID:0/008> tz.mbn
<ID:0/008> hyp.mbn
<ID:0/008> devcfg.mbn
<ID:0/008> pmic.elf
<ID:0/008> rpm.mbn
<ID:0/008> cmnlib.mbn
<ID:0/008> cmnlib64.mbn
<ID:0/008> keymaster.mbn
<ID:0/008> apdp.mbn
<ID:0/008> msadp.mbn
<ID:0/008> sec.dat
<ID:0/008> NON-HLOS.bin
<ID:0/008> storsec.mbn
<ID:0/008> boot.img
<ID:0/008> recovery.img
<ID:0/008> system.img.ext4
<ID:0/008> FAIL! (Auth)
<ID:0/008>
<ID:0/008> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)

When this fails, on the screen of the phone, red text appears that says "secure check fail: system".

Does anyone have any suggestions on what I should do next? Im kind of stumped. Ive been at this for a couple days and cant seem to get different results. I have downloaded several firmwares attempting to resolve this and some of those i believe failed due to bootloader version, but the others typically say fail (auth) or SHA256 is invalid. Although that may be due to me kind of switching between odin 3.13.1 and some patched version of it with this ODIN3B logo in the banner. I would be grateful if anyone could offer me some advice or at least explain what is happening to me. Thank you.