PW11 bootloop after normal reboot — USB enumerates but storage reports 0B, no media

[mainero]

Hi all,

My jailbroken Paperwhite 11th gen has been in a bootloop for about two days and I've run out of ideas. I've done a fair amount of testing already, so I'll lay out everything I know in case it helps narrow things down.

Device

• Paperwhite 11th gen, serial starts with G001PX
• Jailbroken via AdsBreak
• KUAL installed, plus hotfix and HID passthrough (installed roughly 2 months ago)
• I rebooted successfully several times after installing those, with no problems at all
• I don't remember the exact firmware version, and I can't check it now — I'd rather not guess

How it started

The device was at 14% battery. I rebooted it normally — no update, no new install, nothing changed that day. It never came back up. It has been looping ever since.

Boot behaviour

Each cycle shows the Kindle logo (boy under the tree), then an empty progress bar appears, the screen flashes white, and it restarts. The bar never advances beyond a sliver. It has been consistent since the beginning — it doesn't get further or less far between attempts.

What I've ruled out

• Not battery. I charged it for 14+ hours on a 5V/1.5A wall adapter. The loop continued unchanged with a full charge. LED shows green during the cycles, not the low-battery orange.
• Not the cable. My first cable turned out to be charge-only, which cost me a lot of time. With a proper data cable the device does enumerate.

USB behaviour (this is the part I find odd)

With a working data cable on Arch Linux, dmesg shows the device enumerating on every boot cycle:

usb 1-3: New USB device found, idVendor=1949, idProduct=0324, bcdDevice=4.09
usb 1-3: Product: Internal Storage
usb-storage 1-3:1.0: USB Mass Storage device detected
scsi 2:0:0:0: Direct-Access     Kindle   Internal Storage 0409 PQ: 0 ANSI: 2
sd 2:0:0:0: Power-on or device reset occurred
sd 2:0:0:0: [sda] Media removed, stopped polling
sd 2:0:0:0: [sda] Attached SCSI removable disk
usb 1-3: USB disconnect, device number 2

The window is not short — from timestamps, roughly 14 to 24 seconds per cycle between connect and disconnect. But polling lsblk in a loop throughout that window gives me sda 0B every single time, with no partitions and no filesystem detected. fdisk sees nothing either.

So the device presents the mass storage interface but never actually exposes the media. That means I have no way to delete the jailbreak files, drop a hotfix, or do anything else through the USB partition — there is simply nothing there to mount at any point in the cycle.

Questions

1. Does Media removed with a 0B device on every cycle point to the boot dying before userland publishes the storage, or does it suggest the eMMC itself has failed? Is there a way to tell these apart without opening the device?
2. Is there anything left to try over USB that I might be missing, given there's no mountable media?
3. If serial console is the only remaining option — has anyone done UART on a PW11 and can point me to the pad locations and the adapter voltage I'd need? I'm comfortable with a soldering iron but I've never done this on a Kindle.
4. Is there any recovery path for PW11 that doesn't depend on the system reaching userland?

Happy to run any diagnostic you suggest. Screenshots of dmesg, the lsblk output, and the boot screen are attached.

Thanks for any pointers.