You know I can't do that, is there any other way?

No, I believe there is not. You will have to deal with the 3MB flash your current CE has.

I don't think that it has to be all that difficult.

Rather than hot-air it off, or using Chip-Quik, I'm going to nip each leg at the edge of the IC case and unsolder each of the legs from the board individually. I plan to use Plato 170 nippers from Aliexpress. A pack of ten will cost you less than $30 delivered.

I will have made my copy of the contents of the doomed chip beforehand. I strongly recommend everyone to do the same.

Once the chips get here I will give it a shot. Whether it works or not, I'll post the results.

A simpler method is to solder a wire across all the pins and use the iron to apply heat to the wire, allowing the heat to distribute evenly across the pins. I did this on a calculator where I did not want to remove the PCB from the case. Very quick and easy.


Edit: You can also just mix in leaded solder onto all the joins and do multiple quick runs through both rows of pins with some good quality flux and sufficient heat till the chip starts moving

Not sure that it's simpler. I'd say six to one, half dozen to the other. So about the same either way.

My approach was taking into consideration that there would be microscopic resistors and capacitors right next to the serial flash, but no!! TI left the area clean for us! How very kind of them. 🙂

So that makes your method more attractive then I would have expected. And I've seen this method used. It's a great approach in certain conditions, but requires a bit of practice ahead of time.

But for guys who rarely solder, wouldn't it be easier to clip the chip, and then desolder the individual legs? And you are imagining that everyone is going to have nice soldering gear like we do, and not their Grandad's wood burning/urban cowboy cattle branding kit from the sixties.

Keep in mind that the goal is to safely remove the chip, and get the new one in there without having to hear about how someone's kid wrecked their calculator listening to us.

Any bets on how many end up with lifted pads? ;>

(BTW, here's my disclaimer: If anyone tries this at home, well, you're on your own pilgrim).

How does this bypass the OS Verification checks/how is the boot code unlocked? Does it remove that portion of the boot code when you edit the rom for the first time? Is it possible to disable this check on a post M (the target for this project) WITHOUT desoldering the flash chip? (I saw there was an "exploit")

"Note: there is an 8xp version of the installer but it relies on an exploit and therefore can stop working at any time" - is this practacally usable (os downgrades to 5.4 ?)

Looked into it myself - but a new question - is it possible to unlock the boot sector with a programmer, but not replace/remove the chip?

No, not possible. The boot region is OTP locked during flashing at factory

How much more difficult? I have a revision L CE-T.
Also would this work on a 83 Premium CE?