Flashing is possible, but does not work due to these problems:
booting off SD is necessary as system and userdata partitions are too small for the current image
attempting to boot using pmbootstrap flasher boot uploads but fails to boot after printing the cmdline to the screen.
Rooting
The exploit used on the LG Esteem also works on the Optimus Slider. Please see this forum thread on AndroidCentral for instructions. [1]
The tool referenced has a dead download link, but is available through the Internet Archive's Wayback Machine. LG_Esteem_Root.zip on archive.org
The tool runs from a .bat script. Though the changes necessary to run it on linux are trivial, here is the modified script:
run.sh
#!/bin/bash ###################################### # LG Esteem root script# Linux version ## Exploit copyright (C) 2011 Revolutionary# Scripting for LG Esteem by Dan Rosenberg (@djrbliss)# Modified for Linux by foldmorepaper (@foldmorepaper)####################################### # Instructions:# # 1. Ensure you have the latest drivers installed from LG# # 2. Put your device in debugging mode # # 3. Attach it via USB # # 4. Run this script in the same directory as the rest of the extracted# zipfile # ##################################### echo"[*] LG Esteem root script (Linux version)"echo"[*] Exploit copyright (C) 2011 Revolutionary"echo"[*] Scripting for LG Esteem by Dan Rosenberg (@djrbliss)"echo"[*] Linux script by foldmorepaper (@foldmorepaper)"echo"[*]"echo"[*] Before continuing, ensure USB debugging is enabled, that you"echo"[*] have the latest LG drivers installed, and that your phone is"echo"[*] connected via USB."echo"[*]"read-p"[*] Press enter to root your phone..."echo"[*]"echo"[*] Waiting for device..."
adbkill-server
adbwait-for-device
echo"[*] Device found."echo"[*] Pushing exploit binary..."
adbpushzergrush/data/local/tmp/zergrush
adbshell"chmod 755 /data/local/tmp/zergrush"echo"[*] Running exploit..."
adbshell"echo exit | /data/local/tmp/zergrush"# Install the goodsecho"[*] Installing root tools..."
adbshell/data/local/tmp/sh-c"mount -orw,remount /dev/block/system /system"
adbshell/data/local/tmp/sh-c"mkdir /system/tmp"
adbshell/data/local/tmp/sh-c"chmod 777 /system/tmp"
adbpushsu/system/tmp/su
adbpushbusybox/system/tmp/busybox
adbpushSuperuser.apk/system/tmp/Superuser.apk
adbshell/data/local/tmp/sh-c"mv /system/tmp/su /system/xbin/su"
adbshell/data/local/tmp/sh-c"mv /system/tmp/Superuser.apk /system/app/Superuser.apk"
adbshell/data/local/tmp/sh-c"mv /system/tmp/busybox /system/xbin/busybox"
adbshell/data/local/tmp/sh-c"chown root /system/xbin/su"
adbshell/data/local/tmp/sh-c"chmod 4755 /system/xbin/su"
adbshell/data/local/tmp/sh-c"ln -s /system/xbin/su /system/bin/su"
adbshell/data/local/tmp/sh-c"chmod 755 /system/xbin/busybox"
adbshell/data/local/tmp/sh-c"/system/xbin/busybox --install /system/xbin/"# Clean up after ourselvesecho"[*] Cleaning up..."
adbshell/data/local/tmp/sh-c"rmdir /system/tmp"
adbshell"rm /data/local/tmp/* 2>/dev/null"echo"[*] Rebooting..."
adbreboot
adbwait-for-device
echo"[*] Root complete, enjoy!"echo"[*] Press any key to exit."
adbkill-server
Two custom recoveries are available for the vm701. Use in the context of postmarketOS:
CWM
Enable fastboot by formatting the the boot partition
Restore commonly-available Android system backups
TWRP
ADB access without booting Android
To flash a custom recovery to the recovery partition (before having access to fastboot), the tool flash_image is required. (available from, among other sources, BobZhome ROM's) [2]
Fastboot is only available upon erasing/formatting the boot partition. There are alternative means of nulling the boot partition, but CWM is the easiest.
It is recommended, as always, to make a full system backup before doing any modifications. This is especially necessary in this case, as unbricking from emergency mode (camera button + backup button, plug in usb cable to computer) is not possible, even though the lg mobile support tool recognizes the device and downloads a firmware image, an unknown error occurs.
To format the boot partition, Mounts and Storage -> format /boot -> Yes - Format
On boot, fastboot should automatically start. To restore normal boot functionality, restore boot partition from backup.