Friend of mine killed his MacBook with some Softdrink.

Just poured it all over his poor a1502.

He let it dry for a few days, it starts to work again.
Except the battery.

Goes on Amazon and buys a new battery.

New battery doesn't work either and so he tells me about it and I as stupid as I am couldn't resist the temptation to finally work on a MacBook like my "hero" Lois Rossmann does.

So turns out the board is good.
Cleaned it up and basically nothing happened to it.

So what's the deal with "los batlerias"?

The first got hit by liquid, the second had a broken connection to a cell.
That could have happened through my friend, installing it without testing it first, or at the seller, so it being a DOA battery.

Now away from the stupidity of my friend and the situation to the actual source for this rant.

Once something happens to a modern Managed battery, the Battery Management System (BMS) disconnects the voltage from the system and goes into an error state, staying there and not powering anything ever again.
For noobs, it's dead. Buy a new one.

But It can be reset, depending you know how to, and which passwords were set at the factory.
Yes, the common Texas instruments BQ20Zxx chips have default passwords, and apple seems to leav them at default.

The Usb to SMBus adaptors arrived a few days ago and I went to prod the BMS.

There is a very nice available for Windows called BE2works, that I used the demo of to go in and figure out stuff. The full version supports password cracking, the demo not.

After some time figuring out how Smart Battery Systems (SBS) "API" works, I got to actually enter the passwords into the battery to try get into manufacturer and full access mode.

Just to realise, they don't unlock the BMS.

So, to conclude, my friend bought a "new" battery that was most likely cut out of a used / dead macbook, which reports 3000mah as fully charged instead of the 6xxx mah that it should have, with 0 cycles and 0hours used.
And non default access.

This screams after those motherfuckers scaming the shit out of people on Amazon, with refurb, reset, and locked fucken batteries.

I could kill those people right now.

Last but not least,
My friend theoretically can't send it back because I opened the battery to fix the broken connection.
Though maybe, it'll get send back anyway, with some suprise in the package.

TIL that TI has no goddamn chill

Texas Instruments released the TI-83+ calculator model in 1996. The Z80 was not at all stock and has the following features:

- 3 access levels (priveleged kernel, kernel, user)
- Locking Flash (R/O when locked for most pages, some pages protected and unreadable as well, only unlockable from protected Flash pages by reading a certain order of bits then setting a port)
- Locking hardware ports (lock state always the same as flash)
- Customizable execution whitelist range (via locked ports)
- Configurable hardware (Flash/RAM size changeable in software via locked ports, max RAM is 8MB which is fucking mental compared to the 64k in the thing)
- Userland virtualization (always-on)
- Reset on violation of security model
- Multithreading
- Software-overclockable CPU
- Hardware MD5 and cert handling

TI made a calculator in 1996 with security features PCs wouldn't see until like 2010 what the *actual* fuck

for your next edition of "TI's constantly been smoking crack since the 80s and has no intention of ever stopping":

the TI-8x calculators have a hardware buffer and an OS-provided buffer for screen data, effectively being an "immediate" buffer in hardware, to be displayed next VBlank, and a "slower" buffer, being what's copied to the "immediate" buffer when the OS decides it's time to update the screen. All well and good, maybe a little weirdly done but all in all makes sense. (You can even define a third buffer in RAM if you need to triple-buffer your shit.)

The problem arises when you use TI-BASIC and try to draw to the screen:
If you do something like, say, draw a circle, you'll notice that it's visibly drawn to the screen one pixel at a time. However, looking through what bits of the SDK I can find, the OS' "draw circle" assembly routine *doesn't update the immediate buffer!*

This means that, in TI-BASIC, the "draw circle" routine doesn't use the ACTUAL circle-drawing routine the OS provides, but instead individually calculates and plots a pixel, then updates the hardware buffer (an ENTIRE 768 bytes are copied EVERY TIME) and waits for VBlank to pass before repeating for the next one. In other words, it's deliberately slow as fuck.

Why? All the drawing commands, outside of like 2 or 3, do this. Why would you deliberately slow down the process of drawing to the screen on a system that you KNEW would be popular for people to code on???

Time for a 00:30 rant that has no structure!
(There is a theme tho)

TI-BASIC optimization (framecount is from TI-84 Silver, with the higher Z80 clock):

"0→S": 3 frames
"DelVar S": 2 frames
```
0
Ans →S
```
1 frame???
(Variable "Ans" holds the last answer given to the normal calc functions. This makes it blazing fast to use [for some reason])

also refreshing the real TI-8x line's LCD at its actual, normal rate is bad and *SOMEHOW* ends in LCD overvolting (makes parts of the LCD blue instead of dark gray) after ~15 frames. The TI-8x line's normal OS thing refreshes the LCD at 30-45FPS depending on their clock speed, the LCD is native 80FPS. Just figured i should point this out. (Yes, TI, you do make hardware, it's just that sometimes you should make it when SANE)

why the fuck did they make a multitasking machine that runs on a Z80 at, like, 7/8 the original Gameboy's speed (the B/W DMG, the original. The CGB had DoubleSpeed mode.)

When I knew the games on my Texas Instruments calculator was made by simple text files

Taught myself how to program a Texas Instruments 84 graphical calculator to solve the common mathematical equations in high school. Shamelessly copied a lot from the internet but learned quite quickly. Things like solving 2 and 3 degree polynomials, prime factorization or calculating integrals and stuff.
I quite liked how I could make life easier for myself and eventually class mates. Just rolled into software engineering afterwards I guess. No regrets thus far...

Senior year of highschool (5 years ago), my friend and I were bored in Calculus class. The calculators we used were the TI-NSpire CX cas (the most advanced Texas Instruments graphing calculator at that time). After figuring out we could get a Game Boy Advance emulatir on the calculator, we decided we should try making out own game for it. That was when I figured out what I wanted to do with my life and havent looked back yet

I honestly can't remember which I used first, but my dad had a monochrome apricot with snake and a Texas instruments with Parsec. I think we still have the TI lying around somewhere.

I remember it being something we shared an interest in and it's a shame most parents today view games as a babysitting tool at best.