Troubleshooting Bricked PW3 (G090G1) - Accidentally dd'ed firmware to /dev/sda, now showing 0B / No M

[arungop]

Hi everyone,

I accidentally bricked my Kindle Paperwhite 3 (WiFi, 4GB, Black - Serial Prefix: G090G1) while trying to work on it.

The Mistake:
I accidentally ran a dd command pointing a firmware .bin file directly at the raw device path (/dev/sda). This appears to have completely overwritten or corrupted the MBR / partition table.

Current Behavior:

lsusb output: The device is still alive and responds with standard Amazon identifiers:
Bus 003 Device 014: ID 1949:0004 Lab126, Inc. Amazon Kindle 3/4/Paperwhite

lsblk output: It shows up as sda, but registers as 0 bytes:
sda 8:0 1 0B 0 disk

Errors: Running sudo fdisk /dev/sda, partprobe, or blockdev --rereadpt all return: No medium found or Error opening /dev/sda.

What I have tried so far:

fastboot devices: Returns absolutely nothing.

imx_usb_loader: I compiled imx_usb and tried pushing the u-boot.bin from imx60_wario, but it returns no matching USB device found. This makes sense because lsusb shows it is still identifying as 1949:0004 rather than the Freescale HID bootloader mode (15a2:0063).

Hard Resets: Holding the power button for 40–60 seconds while plugged in or unplugged restarts the loop, but it always enumerates back as 1949:0004 with a 0B block size.

Because the partition table is scrambled, the Kindle's USB mass storage profile seems stuck presenting an empty slot. Since I can't force it into USB Downloader Mode via the power button and fdisk can't open the device, I'm stuck.

Is there a known software trick to force the i.MX6 processor to drop into 15a2:0063 recovery mode when the storage is corrupted like this, or am I officially looking at a hardware battery-drain wait / soldering a UART serial connection?

Thanks in advance for any insights!