Constant reboot

@James L -- How do you do a factory reset when you can't get it to boot? How do you do a firmware flash?

It does not recognize/respond to holding Power+VolDown -- it just continues in the reboot cycle. Holding Power+VolUp+Home is also not recognized. I am unable to turn off the tablet -- it does not respond to the Power button. As noted in the original post, holding VolUp got it to the "Install system update" screen but only for a split second then it displayed the "Error" screen.

Overnight, it ran down the battery (due to the constant reboots). So I plugged it in again this morning but no change in behavior or in responsiveness to the various key presses.

The "sammobile firmwares" site does not list a US version of firmware for this model. I did find some here.

I'll search around for Odin. I had it some years ago but haven't had to use it in a while.

UPDATE: I was finally successful getting the download screen to appear so maybe once the FW is downloaded, I can get it working again.

Well, I downloaded Odin3 (v3.12.3) and downloaded the FW update (XAR-T380DXU3CSK1-20191125134039) from https://samfrew.com/model/SM-T380/. I selected the AP file and after the MD5 was confirmed (this page said I only needed the AP file), I clicked start but it failed (see below).

<ID:0/003> 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..
<ID:0/003> Odin engine v(ID:3.1203)..
<ID:0/003> File analysis..
<ID:0/003> SetupConnection..
<ID:0/003> Initialzation..
<ID:0/003> Get PIT for mapping..
<ID:0/003> Firmware update start..
<ID:0/003> SingleDownload.
<ID:0/003> boot.img.lz4
<ID:0/003> FAIL!
<ID:0/003>
<ID:0/003> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)

So, then I saw this page which says you always need to flash all of the files. This set didn't include the CP (modem) but I tried flashing the BL, AP, and HOME_CSC. But it got to a point and just stopped (see below). It is still just sitting there.

<ID:0/003> 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..
<ID:0/003> Odin engine v(ID:3.1203)..
<ID:0/003> File analysis..
<ID:0/003> skip file list for home binary
<ID:0/003> aboot.mbn.lz4
<ID:0/003> sbl1.mbn.lz4
<ID:0/003> rpm.mbn.lz4
<ID:0/003> tz.mbn.lz4
<ID:0/003> devcfg.mbn.lz4
<ID:0/003> cmnlib.mbn.lz4
<ID:0/003> keymaster.mbn.lz4
<ID:0/003> apdp.mbn.lz4
<ID:0/003> msadp.mbn.lz4
<ID:0/003> NON-HLOS.bin.lz4
<ID:0/003> lksecapp.mbn.lz4
<ID:0/003> sec.dat.lz4
<ID:0/003> boot.img.lz4
<ID:0/003> recovery.img.lz4
<ID:0/003> system.img.ext4.lz4
<ID:0/003> persist.img.ext4.lz4
<ID:0/003> userdata.img.ext4.lz4
<ID:0/003> modem.bin.lz4
<ID:0/003> adspso.bin.lz4
<ID:0/003> cache.img.ext4.lz4
<ID:0/003> Home Binary Download
<ID:0/003> SetupConnection..
.

I've uploaded the image of the download screen where it is sitting and of the model tag.

I found this page which describes applying a custom recovery. Best next option?
.