Restoring Windows on ASUS T101HA

Complete guide to reverting from Xubuntu back to the original Windows installation.

What you have

Verified: SHA256 CBD4348ACB6777D5110D00F15FD67A6CBABE96152B628E503A8F2F6127E4EB63 (both copies identical)

Image expands to: 62,537,072,640 bytes — exact match to device size

Device reference

• Internal eMMC: /dev/mmcblk1 — ~58GiB (62,537,072,640 bytes)
• Firmware: 64-bit UEFI (confirmed via fw_platform_size)
• Original layout: ESP, Microsoft reserved, Windows (p3), recovery (p4)

WARNING: Verify the device with lsblk every time. Device names can shift between boots.

Method 1 — Full image restore (recommended)

Restores the exact original system: Windows activated, ASUS recovery partition, everything.

Preparation

If the image lives on the PC, copy it back to the USB stick's BACKUP partition first. Restoring over a network is not recommended.

Steps

1. Boot the Ventoy live session

Power off fully. Hold F2, tap power, keep holding. Confirm Secure Boot is disabled, boot from USB, select the Xubuntu ISO, choose "Try Xubuntu".

2. Identify the devices

lsblk -o NAME,SIZE,FSTYPE,LABEL,MOUNTPOINT

Confirm:

• eMMC = the ~58GiB device (mmcblk1)
• USB = the ~115GiB device with Ventoy/VTOYEFI/BACKUP partitions

3. Mount the backup

sudo mkdir -p /mnt/backup
sudo mount /dev/sda3 /mnt/backup
ls -lh /mnt/backup

Adjust sda3 to match the BACKUP partition from step 2.

4. Verify the image before writing

zstd -t /mnt/backup/t101ha.img.zst

Must complete without error. If it fails, use the PC copy instead — do not proceed with a corrupt image.

5. Restore

sudo blockdev --getsize64 /dev/mmcblk1

Confirm this prints 62537072640. Then:

zstd -dc /mnt/backup/t101ha.img.zst | sudo dd of=/dev/mmcblk1 bs=4M status=progress
sync

WARNING: of= is the destructive direction. Everything on that device is erased. Read the command twice before pressing Enter.

Takes 1–2 hours. Do not interrupt it, and do not run anything else — 2GB RAM.

6. Finish

sync
sudo umount /mnt/backup
sudo poweroff

Remove the USB stick. Power on. Windows should boot, activated, exactly as it was.

With a progress bar

sudo apt install -y pv
sudo sh -c 'zstd -dc /mnt/backup/t101ha.img.zst | pv -s 62537072640 | dd of=/dev/mmcblk1 bs=4M'

Method 2 — Recover files only (non-destructive)

To extract files from the Windows image without wiping Xubuntu. Requires ~58GB free space.

zstd -d /path/to/t101ha.img.zst -o /tmp/full.img
sudo losetup -fP --show /tmp/full.img

Note the loop device it prints (e.g. /dev/loop0), then:

sudo mkdir -p /mnt/win
sudo mount -o ro /dev/loop0p3 /mnt/win

Windows lives on partition 3. Browse /mnt/win, copy what you need.

Cleanup:

sudo umount /mnt/win
sudo losetup -d /dev/loop0
rm /tmp/full.img

If mount fails withttps://account.microsoft.com/devices/recoverykey

Method 3 — Clean Windows install (image lost)

Last resort. The product key is stored in firmware (ACPI MSDM table), so a clean install self-activates without entering anything.

1. Download the Windows 10 ISO from Microsoft on the PC
2. Write it to USB with Rufus — GPT, UEFI target
3. Boot the tablet from it, install to the internal eMMC
4. Activation happens automatically from firmware

Caveats:

• The ASUS recovery partition is not restored
• Cherry Trail drivers may need manual installation from ASUS support
• Windows 10 is past end of support (October 2025), and this hardware cannot run Windows 11 — a restored image is a supported-nothing situation either way, but a clean install is strictly worse

Recovering the product key

From Linux, on the running tablet:

sudo strings /sys/firmware/acpi/tables/MSDM | tail -1

From the saved file:

cat /mnt/backup/window-key.txt; echo

From Windows:

(Get-CimInstance SoftwareLicensingService).OA3xOriginalProductKey

Note: viewing window-key.txt in Notepad may show CJK garbage — it's an encoding guess, not corruption. Read it on Linux with cat, or open it in VS Code and set encoding to UTF-8.

Verifying image integrity

Quick check (structural):

zstd -t t101ha.img.zst

Full check (byte count vs device):

DEV=$(sudo blockdev --getsize64 /dev/mmcblk1)
IMG=$(zstd -dc /path/to/t101ha.img.zst | wc -c)
echo "device: $DEV"
echo "image:  $IMG"
test "$DEV" = "$IMG" && echo MATCH || echo MISMATCH

Compare copies (PowerShell):

Get-FileHash 'path\to\t101ha.img.zst' -Algorithm SHA256

WARNING: [ "$DEV" = "$IMG" ] requires spaces inside the brackets. Without them the shell reports "command not found" and prints MISMATCH regardless of the actual values. Use test to avoid this.

Troubleshooting

Restore finishes but won't boot

Check Secure Boot in BIOS — re-enable it, since the original Windows install expects it. Confirm the boot order lists Windows Boot Manager.

dd reports "No space left on device"

Wrong target device. Verify with lsblk that you're writing to the ~58GiB eMMC.

Image fails zstd -t

Use the other copy. If both fail, fall back to Method 3.

Progress appears frozen

Check it's actually stalled before interrupting:

ps -eo pid,stat,cmd | grep -v grep | grep -E 'dd|zstd'
sudo dmesg | tail -30

STAT D plus mmc errors in dmesg indicates bad sectors. STAT R/S with a clean dmesg means it's just slow — eMMC on this tablet throttles when warm.

"read kernel buffer failed"

dmesg needs root here: sudo dmesg

Notes

• Keep both copies of the image. The USB stick is a single point of failure.
• Restoring reverts to the disk state as of 27 July 2026. Nothing created in Xubuntu survives.
• Do a full zstd -t on whichever copy you plan to use before wiping anything.
• Original image created with: sudo zstd -1 -T0 -f -o /mnt/backup/t101ha.img.zst /dev/mmcblk1