Kindle 10th gen (kt4) serial console

[mistyk]

Following the diagram from this post I was able to get a serial console connection with a kt4, here's my boot log attached and here's the output by pressing a key at boot time:

...
In:    serial
Out:   serial
Err:   serial
switching back to PMIC user mode
force_idle_bus: sda=0 scl=1 sda.gp=0x1 scl.gp=0x0
failed to clear bus, sda=0 scl=1
Hardware Board: EVT
Board ID is P091M80413148A24
WFO module
secure_cpu: 1, production: 1, unlocked: 0
Boot mode is 0
Hit any key to stop autoboot:  0 
fl
Enter fastboot mode, use Ctrl+C to exit.

Why I'm doing this? The kindle is no longer detected by a computer using a USB port (It froze while using koreader), it boots fine, it charges fine but the battery drains really fast (it was fine before this).

My goal is to reflash the same firmware or at least copy the firmware file to the kindle and try to update it from there and see if that can fix it. The kindle is jailbroken.

I compiled the kindle's fastboot version from this link and it appears to work but does not detect the kindle while in fastboot mode, maybe my TX and RX connections are not very good since my soldering skills are very limited? is it possible to log in into the kindle instead of going into fastboot directly? Maybe in that way I can mount the fat partition somehow? Any help or guidance on what could I try next would be very helpful.

lastboot.txt in spoiler too for readability:

Spoiler:

HW

U-Boot 2016.03 (Feb 19 2020 - 18:42:36 +0000)

CPU:   Freescale i.MX6SLL rev1.1 996 MHz (running at 792 MHz)
CPU:   Commercial temperature grade (0C to 95C) at 62C
Reset cause: POR
Board: MX6SLL Rex
I2C:   ready
DRAM:  512 MiB
read voltage pass, retry=20
MMC:   FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2
idme_initialize
Idme version is 2.x and set related function to V2.x
IDME table version 2.1
hibernation: Not from hibernation
Core : f770ee83 2018/03/16 19:49:02 (Licensed to Amazon Fulfillment Services,Inc..)
SBIOS: v2.0 2022/09/21 17:13:01
TTBR:9fffc059
Platform: v2.0 2022/09/21 17:13:01
fl
*** Warning - bad CRC, using default environment

In:    serial
Out:   serial
Err:   serial
switching back to PMIC user mode
force_idle_bus: sda=0 scl=1 sda.gp=0x1 scl.gp=0x0
force_idle_bus: failed to clear bus, sda=0 scl=1
Hardware Board: EVT
Board ID is P091M80413148A24
WFO module
secure_cpu: 1, production: 1, unlocked: 0
Boot mode is 0
Hit any key to stop autoboot:  0 
boota mmc1 
boota: trying to boot from partition: kernel
Certificate authenticated
==============
Image Metadata
==============
product:jaeger
signer:CodeSigner
Image AUTHENTICATED with PRODUCTION certificate
kernel   @ 83008000 (6724816)
ramdisk  @ 84000000 (6604288)
fdt      @ 83f00000 (124543)
## Booting Android Image at 0x80800000 ...
Kernel load addr 0x83008000 size 6568 KiB
Kernel command line: console=ttymxc0,115200 consoleblank=0 uart_at_4m root=/dev/mmcblk1p8 rootwait quiet secure_cpu=1 androidboot.secure_cpu=1 ande
## Flattened Device Tree blob at 83f00000
   Booting using the fdt blob at 0x83f00000
## Traversing FDT blob at 0x83f00000 for imx6sll-jaeger-wfo.dtb at offset 0x8
Found imx6sll-jaeger-wfo.dtb at 0x83f16bf0, len 0x7a6a
   OK to initialize idme device tree
   Loading Kernel Image ... OK
   Loading Ramdisk to 9e7a0000, end 9edec600 ... OK
   Using Device Tree in place at 83f16bf0, end 83f21659

Starting kernel ...

[    0.000000] L2C-310: enabling full line of zeros but not enabled in Cortex-A9
[    0.207820] bd71827 0-004b: Reboot Reason: PWRON_LONGPRESS      Long Pressed Power Button Shutdown
[    0.242921] idme_init: 0 2
[    0.369985] IRQ# for BT HOST WAKE: 120
[    0.614459] cpu cpu0: dev_pm_opp_get_opp_count: device OPP not found (-19)
4.1.15-lab126 #1 SMP PREEMPT Tue Aug 1 11:50:21 UTC 2023 armv7l
[    0.901485] requesting waveform imx/epdc/epdc_default_wfm.fw
cannot write vcom err=-5
[    2.603783] imx_epdc_v2_fb 20f4000.epdc: Update region is outside bounds of framebuffer.Aborting update.
BOOTING DEFAULT.
IP-Config: no devices to configure
kinit: Mounted root (ext3 filesystem) readonly.
info sytem:mounted_proc::
info system:mounted_sys::
info system:sy00::
info system:mounted_dev::
info milestone:4.23:49.1:49.1
info milestone:4.27:49.2:49.2
info milestone:4.30:49.3:49.3
info milestone:4.36:49.4:49.4
info milestone:4.39:49.5:49.5
info sytem:mounted_tmpfs::
info milestone:4.46:sy50:sy50
info system:start:time=4490:time=4490
info hardware:no_wan:: WiFi only device. No WAN found
info milestone:4.61:sy51:sy51
lipc-send-event[288]: E lipc:con::Connection error(Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory)
lipc-send-event[288]: C def:dbusi::Failed to init dbus
lipc-send-event[288]: E def:open::Failed to open LIPC
lipc-send-event[288]: E def:fail:source=com.lab126.hal, event=powerButtonPressed:Sending event failed
lipc-send-event[330]: E lipc:con::Connection error(Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory)
lipc-send-event[330]: C def:dbusi::Failed to init dbus
lipc-send-event[330]: E def:open::Failed to open LIPC
lipc-send-event[330]: E def:fail:source=com.lab126.hal, event=mmcIn:Sending event failed
lipc-send-event[333]: E lipc:con::Connection error(Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory)
lipc-send-event[333]: C def:dbusi::Failed to init dbus
lipc-send-event[333]: E def:open::Failed to open LIPC
lipc-send-event[333]: E def:fail:source=com.lab126.hal, event=usbPlugIn:Sending event failed
lipc-send-event[339]: E lipc:con::Connection error(Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory)
lipc-send-event[339]: C def:dbusi::Failed to init dbus
lipc-send-event[339]: E def:open::Failed to open LIPC
lipc-send-event[339]: E def:fail:source=com.lab126.hal, event=usbPlugIn:Sending event failed
info milestone:6.01:sy99:sy99
info system:done:time=6040:time=6040
crond[350]: crond (busybox 1.34.1) started, log level 8

init.exe: sshd main process (349) terminated with status 127
init.exe: sshd main process ended, respawn�i�
--- SORRY, LOGIN IS DISABLED ON DEVICE ---
info milestone:6.36:sc01:sc01
info system_fs_loopbacks:mountingfs:Mounting compressed directories filesystem images:Mounting compressed directories filesystem images
info milestone:6.39:sc02:sc02
info milestone:6.44:/usr/share/X11/xkb:/usr/share/X11/xkb
info system_fs_loopbacks:mounted:Image /usr/share/X11/xkb.sqsh mounted:Image /usr/share/X11/xkb.sqsh mounted
info milestone:6.52:3:3
info milestone:6.52:sc05:sc05
info milestone:6.54:/usr/java/lib/fonts:/usr/java/lib/fonts
info system_fs_loopbacks:mounted:Image /usr/java/lib/fonts.sqsh mounted:Image /usr/java/lib/fonts.sqsh mounted
info milestone:6.61:4:4
info milestone:6.62:sc05:sc05
info milestone:6.63:/etc/kdb.src:/etc/kdb.src
info system_fs_loopbacks:mounted:Image /etc/kdb.src.sqsh mounted:Image /etc/kdb.src.sqsh mounted
info milestone:6.70:5:5
info milestone:6.71:sc05:sc05
info milestone:6.72:/usr/lib/locale:/usr/lib/locale
info system_fs_loopbacks:mounted:Image /usr/lib/locale.sqsh mounted:Image /usr/lib/locale.sqsh mounted
info milestone:6.78:6:6
info milestone:6.79:sc05:sc05
info milestone:6.81:/usr/share/keyboard:/usr/share/keyboard
info system_fs_loopbacks:mounted:Image /usr/share/keyboard.sqsh mounted:Image /usr/share/keyboard.sqsh mounted
info milestone:6.98:7:7
info milestone:6.99:sc05:sc05
info milestone:7.00:/opt/var/local:/opt/var/local
info system_fs_loopbacks:mounted:Image /opt/var/local.sqsh mounted:Image /opt/var/local.sqsh mounted
info milestone:7.07:8:8
info milestone:7.08:sc05:sc05
info milestone:7.09:/etc/uks:/etc/uks
info system_fs_loopbacks:mounted:Image /etc/uks.sqsh mounted:Image /etc/uks.sqsh mounted
info milestone:7.17:9:9
info milestone:7.18:sc05:sc05
info milestone:7.19:/usr/lib/tts:/usr/lib/tts
info system_fs_loopbacks:mounted:Image /usr/lib/tts.sqsh mounted:Image /usr/lib/tts.sqsh mounted
info milestone:7.27:10:10
info milestone:7.28:sc05:sc05
info milestone:7.29:/usr/lib/mmseg:/usr/lib/mmseg
info system_fs_loopbacks:mounted:Image /usr/lib/mmseg.sqsh mounted:Image /usr/lib/mmseg.sqsh mounted
info milestone:7.37:11:11
info milestone:7.38:sc05:sc05
info milestone:7.39:/app/tools:/app/tools
info milestone:7.40:sc04:sc04
warn system_fs_loopbacks:mountpointmissing:Image /app/tools.sqsh not mounted, non existing mounting point:Image /app/tools.sqsh not mounted, non et
info milestone:7.42:sc05:sc05
info milestone:7.43:/usr/lib/webkit-gtk:/usr/lib/webkit-gtk
info system_fs_loopbacks:mounted:Image /usr/lib/webkit-gtk.sqsh mounted:Image /usr/lib/webkit-gtk.sqsh mounted
info milestone:7.50:12:12
info milestone:7.51:sc05:sc05
info milestone:7.52:sc07:sc07
info system:emiting_event:mounted_fs_loopbacks:mounted_fs_loopbacks
debug sytem:event_emitted:mounted_fs_loopbacks:mounted_fs_loopbacks
info system:emiting_event:loaded_modules_dependencies:loaded_modules_dependencies
info milestone:7.58:fs75:fs75
debug sytem:event_emitted:loaded_modules_dependencies:loaded_modules_dependencies
info system:emiting_event:loaded_fuse:loaded_fuse
debug sytem:event_emitted:loaded_fuse:loaded_fuse
info modules:modprobe:loading module falcon:loading module falcon
info milestone:7.65:fs00:fs00
info system:emiting_event:loaded_falcon:loaded_falcon
debug sytem:event_emitted:loaded_falcon:loaded_falcon
info hardware:no_wan:: WiFi only device. No WAN found
info filesystems_keys:mouting_keys:mounting keys partition:mounting keys partition
info system:emiting_event:loaded_cdc_ncm:loaded_cdc_ncm
debug sytem:event_emitted:loaded_cdc_ncm:loaded_cdc_ncm
info system:emiting_event:mounted_keys:mounted_keys
info system:emiting_event:loaded_fakekey:loaded_fakekey
debug sytem:event_emitted:mounted_keys:mounted_keys
debug sytem:event_emitted:loaded_fakekey:loaded_fakekey
info milestone:7.85:fs40:fs40
info filesystems_var_local:File system errors checked. Return code 0:Warning: skipping journal recovery because doing a read-only filesystem check.
LocalVars: clean, 1364/65536 files, 42743/262144 blocks:Warning: skipping journal recovery because doing a read-only filesystem check.
LocalVars: clean, 1364/65536 files, 42743/262144 blocks
info filesystems_var_local:No file system errors::
info filesystems_var_local:DB PARAMS:FreePageSize:0 bytes. AvailableSpaceInVarLocal:206208 KB.:FreePageSize:0 bytes. AvailableSpaceInVarLocal:2062.
info milestone:8.35:fs23:fs23
info system:emiting_event:mounted_varLocal:mounted_varLocal
debug sytem:event_emitted:mounted_varLocal:mounted_varLocal
info milestone:8.49:vi00:vi00
info touch:detect:enable touch regulators:enable touch regulators
info milestone:8.64:vi99:vi99
info prereg:PRAGMA_QUICK_CHECK_PASSED:: sts=0
info display:started:time=8700:time=8700
info system:emiting_event:display_ready:display_ready
info filesystems_nh:createnh:link already exists:link already exists
debug sytem:event_emitted:display_ready:display_ready
info system:emiting_event:mounted_nh:mounted_nh NH_REALLY_MOUNTED=1
info milestone:8.92:fs25:fs25
debug sytem:event_emitted:mounted_nh:mounted_nh NH_REALLY_MOUNTED=1
info milestone:8.97:fs30:fs30
info n_setup:n_setup started::
info system:emiting_event:n_ready:n_ready
debug sytem:event_emitted:n_ready:n_ready
info n_setup:n_setup stopped::
info userstore:run:time=9420,action=start:time=9420,action=start
info userstore:start:found_bootup_flag:found_bootup_flag Found BOOTUP flag file
info touch:detect:detect touch devices:detect touch devices
err mntus:loopback_not_mounted:: loopback device is not set-up : losetup: /dev/loop/0: No such device or address
info touch:detect:disable touch regulators:disable touch regulators
info touch:detect:install Parade touch driver:install Parade touch driver
[    9.761575] cyttsp5_i2c_adapter 1-0024: cyttsp5_get_hid_descriptor_: failed to get HID descriptor length and version, rc=-5
[    9.782398] cyttsp5_i2c_adapter 1-0024: cyttsp5_startup_: Error on getting HID descriptor r=-5
info cyttsp5:update:cyttsp5 fw ver=0x307 file version=0x307:cyttsp5 fw ver=0x307 file version=0x307
info system:emiting_event:loaded_touch:loaded_touch
debug sytem:event_emitted:loaded_touch:loaded_touch
info mntus:fs_error_recover:: File system errors recovered
info system:emiting_event:mounted_userstore:mounted_userstore
debug sytem:event_emitted:mounted_userstore:mounted_userstore
info milestone:11.42:fs50:fs50
info milestone:11.60:fs90:fs90
info filesystems_setup:Not create ENABLE_UNIFIED_STICKYNOTE_CX flag::
info battery:charged:cap=,mV=,mAH=:cap=,mV=,mAH=
info system:emiting_event:battery_ready:battery_ready
info filesystems_setup:Create /app/bin/KPPMainApp to /app/bin/KPPMainAppV2::
debug sytem:event_emitted:battery_ready:battery_ready
info filesystems_setup:Update file absent or failed to backup::
info milestone:12.02:fs99:fs99
info milestone:12.08:sys99:sys99
info system_setup:system_setup_after_shpm done::
info system:emiting_event:dbus_ready:dbus_ready
debug sytem:event_emitted:dbus_ready:dbus_ready
info dbus:check-update:status=2:status=2 dbus_ready sent
info demd:starting...::
info perfd:starting...::
info hardware:no_wan:: WiFi only device. No WAN found
info milestone:13.59:dy01:dy01
info milestone:13.70:pm25:pm25
info milestone:13.71:tt25:tt25
info milestone:14.21:dy02:dy02
info milestone:14.24:dy03:dy03
info system:emiting_event:x_should_start:x_should_start
debug sytem:event_emitted:x_should_start:x_should_start
info milestone:15.87:xx00:xx00
info X:load:time=16010:time=16010
info X:xorg.conf:Generating xorg.conf:Generating xorg.conf
info stopVoiceView:entered:arg=deleteAsrFlags:arg=deleteAsrFlags
info stopVoiceView:Deleting ASR Flags::
info X:xorg.conf:xorg.conf generated:xorg.conf generated
info milestone:18.44:xx50:xx50
info X:starting:time=18690:time=18690
info milestone:22.44:xx99:xx99
info X:started:time=22470:time=22470
info system:emiting_event:x_setup_ready:x_setup_ready
debug sytem:event_emitted:x_setup_ready:x_setup_ready
info bootactions:starting...::
info bootactions:waiting:for:for lipc...
info system:emiting_event:bootactions_ready:bootactions_ready
debug sytem:event_emitted:bootactions_ready:bootactions_ready
info register_oobe:registering...::
info register_oobe:done...::
info asr_setup:Not in asr mode::reason=flag file not present. shutting down asr_setup::
info milestone:28.10:lp00:lp00
info milestone:28.31:lp01:lp01
info milestone:28.35:lp02:lp02
info locale:read:lang=en_US.utf8,lc_all=en_US.utf8:lang=en_US.utf8,lc_all=en_US.utf8 Retrieved Language
info system:emiting_event:langpicker_ready:langpicker_ready LANG_PICKER_SCREEN_SHOWN=0
debug sytem:event_emitted:langpicker_ready:langpicker_ready LANG_PICKER_SCREEN_SHOWN=0
info milestone:28.61:lp0300:lp0300
info starting:ffsd...::
info lab126_gui:KPP OOBE flag found...Showing KPP Progress Bar::
err unable:to:start:start ffsd mode ZTS
info ffsd:stopped...::
info asr_bt_reboot:asr_bt_reboot begin on started winmgr_ready::
info hardware:no_wan:: WiFi only device. No WAN found
info milestone:29.66:pi00:pi00
info milestone:30.02:pi99:pi99
info system:emiting_event:contentpack_font_ready:contentpack_font_ready
debug sytem:event_emitted:contentpack_font_ready:contentpack_font_ready
info milestone:32.98:fr00:fr00
info milestone:33.13:fr50:fr50
info milestone:33.17:fr51:fr51
info framework:starting:time=34840:time=34840
info framework:commandLine:HEAP = -Xmx45m -Xms45m  -XX:MaxNewSize=4m -XX:SurvivorRatio=3 -XX:TargetSurvivorRatio=80 -Xss100k -XX:ReservedCodeCachel
info hardware:no_wan:: WiFi only device. No WAN found
info framework:##### Starting Java SE8 VM ::
info milestone:69.60:fr99:fr99
info framework:started:time=69650,delta=36490:time=69650,delta=36490
warn framework_setup:cannot get ffsdStatus::
info framework_setup:ffs Status=::
info framework_setup:ffsd is not active or ffs is complete::
info blanket_f:loading blanket module:usb:usb
info system:emiting_event:framework_ready:framework_ready
debug sytem:event_emitted:framework_ready:framework_ready
info bridge:start:: hello there! (r17398)
info bridge:start:: so uncivilized
info bootactions:stopped...:: 
info stored:started::               
info fastmetrics:starting...::   
info stored:read_in_counters:REBOOTS=0, REBOOT_LIMIT=1, RESTARTS=0, RESTART_LIMIT=5:REBOOTS=0, REBOOT_LIMIT=1, RESTARTS=0, RESTART_LIMIT=5
info monitor:writing_file:file=/var/run/upstart/stored.restarts:file=/var/run/upstart/stored.restarts
info clickstreamHeartbeatMetricsFramework:Skipping metrics recording, as it is the same day::
Retrieved 452 keys for system/daemon/pmond/