Approving ADB debugging on a broken-touch android

I like to play with partially broken phones and tablets. Well, kind of anyway, it comes with it’s own frustrations, but they’re an often overlooked source of hardware. Most of their neat things (screen, sensors, audio, wifi, bluetooth..) aren’t really possible to separate out – things are so integrated now – but they also come with their own CPU/GPU. Often a powerhouse by embedded standards, certainly enough to pass things along to a lesser but more accessible arduino or desktop. I tend toward android, because even though it’s not a raspberry pi, they’re somewhat linux-ish, and can often be made to run something approximating a small server with Deploy Linux, kbox3, termux, or even just busybox with some add-ons.

Very often, the main issue is that either the screen is broken or the screen works but has no touch capability. No-screen you’re usually stuck flashing something custom (depends a lot on device) but on many devices, no-touch (but working screen) can be handled by plugging in a mouse/keyboard via usb-otg. That is, one of those little wires with usb-micro-b on one end and a USB female (as you see on a hub or computer) to plug the mouse/kb/combo into on the other end. With this, you’ll often get a mouse pointer, and you can (sort of) limp yourself along installing something more permanent.

However, if it’s a fairly recent android, you’ll soon bump into another roadblock. Ok, I just did, not sure about others. Trying to activate USB adb debugging (so you can shell in from desktop, push/pull apps and data, root it, so on) requires both the usb port (pops up a permissions box) *and* touch or mouse (to click ok). If you disconnect the usb to the desktop, the popup goes away.

If you have root (or other enhanced access), you can add a key in /data/misc/adb/adb_keys and set a local variable (ADB_KEY on windows) to match, letting you in without he OK. If you it’s a debug build, you can do “adb disable-verity” to disable checking it. I had neither. So, another way around I saw mentioned is a bluetooth mouse. If you have one, pair that (can be done with the usb mouse in), good to go. If you don’t (me) you can use TrueMouse Lite on another, non-broken, android to fully emulate a mouse. There’s a ton of other remotes, but most require an app on the client side, and usually android isn’t supported. TrueMouse does require root, and is a 9 day trial, but it shows up as a true BT mouse. So any other rooted and functioning android, in my case an LG Fuel from a $5 special tracfone sale, works. Click the OK, boom, access.

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