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CMIzapper  Technology for your Mac repair business

CMIzapper Medusa 2/3 firmware changes

Firmware version 1.1 runs on the Medusa 2 with a 4 position DIP switch.

Firmware version 2.0 switches to different hardware that has a 5 position DIP switch. Added the option to clean the ME region (ME: 9.0 9.1 9.5 10.0)

Firmware version 2.1 Changed the way the $SVS block is cleared as Apple made a small change as of High Sierra. The 'old' way probably still works but, whatever you do, always make a backup of the Mac ROM before doing anything (but you were doing that already, right?).

Changed the way that the unlocked/locked status of the Mac is detected to work under High Sierra.

Now shows more characters of the Mac Firmware version to reflect new Apple firmware naming policy (e.g. they jump from MB91.0154.B21 to MB91.0155.B01 rather than only update the Bxx part).

Changed the way that the ME Region is cleaned.

Added the option to clean the PRAM in models with ME version 8 or higher..

Firmware version 2.2 Added the option to fix the checksum of the Fsys block. Useful if the serial number has been edited by someone who did not update the checksum.

Firmware version 2.3 Added the option to copy and paste the Mac serial number. Useful if you fix a Mac by swapping the motherboard but you want it to keep the old serial number.

Firmware version 2.4 Now shows the amount of records in the PRAM block. Added the option to clean the PRAM in all models

Firmware version 2.5 (Added the ability to clean the ME in the MacBook A1534 emc3097 (Mid 2017).  

Firmware version 2.6 Improved compatibility with TL866 SPI programmers. Pressing the button now skips to the next item when showing all information from the Mac ROM.

Firmware version 2.7 Added support for the new Medusa keyboard enabling editing of the serial number.

Firmware version 2.8 Changed to new hardware to be firmware compatible with upcoming Medusa 3.

Firmware version 2.9 Changed the way sectors are erased to be more persistent and at the same time to give diagnostic info in case the erasing is not working as expected. Added the ability to clean ME in 820-2849 and 820-2850. Now also shows motherboard numbers for 820-2337, 820-2849 and 820-2850 and a few more models.

Firmware version 3.0 Added the option to write the 'gpu-power-prefs' nvram-variable. This turns off the external (discrete) GPU in those Macs that have one. This is mostly useful in case of the 15-inch and 17-inch models of the MacBook Pro 2011, where the GPU dies in 'a small percentage of MacBook Pro systems'. (Apple-speak for: 'very many') If you set this variable Macbooks with a dead GPU will magically work again by only using the internal GPU, that is, until you clear the NVRAM (PRAM).

Firmware version 3.1 Improved the routine that writes the serial number to update all occurrences of the serial number in the Fsys block (both 'ssn' and 'SSN' records), not just the first one.

Fixed an issue with the ROM reset where a delay is required after issuing a reset. Depending on the ROM chip involved that could result in Mode-0 (Show all data) not working.

Added a screen to Mode-0 that will show the exact type of ROM chip using information from the SFDP in the ROM. This because I am quite fed up of getting fake chips that are one model, but have a different model printed on them. This will show their true identity.

Firmware version 3.2 Improved the routine that shows the voltage information from the SFDP in the ROM. Now the voltage information is also pulled from SFDP data blocks larger than 256 bytes. Added Mode-24 to view the SFDP data (first 256 bytes only).

Added support for some Chromebooks. The Hardware-ID is shown, hopefully on all models. All sorts of parameters are shown for many models, and the serial number is shown for some models. Serial number can be written on some models.

Added Mode-22 to 'Blank-Boardify' a board.

Firmware version 3.3 Improved the routine that shows the voltage information from the SFDP in the ROM. Now Adesto and Microchip ROMs are supported too.

The Medusa will now also recognise the ROM for the T2 chip. To read or write the T2 ROM you will have to remove the ROM from the Mac and you also need the Medusa Level Shifter board.

For T2-ROM: Added the ability to edit the Mac serial number in the ROM for the T2 chip. Shows the motherboard serial number.

Firmware version 3.4 Improved the routine that edits the serial number of a Mac. In earlier versions some Macs would trigger an 'out of range error' in the Medusa.

For T2-ROM: Added the ability to show the Boot ROM version.

Understands the 128Mbit ROMs as used in the iMac 2019 models. All function work for the iMac 2019 except clean ME and read/write the whole ROM.

Firmware version 3.5 Improved the routine that shows the Mac motherboard PCB number (820-xxxx). It can now tell the 11-Inch and 13-Inch MacBook Air apart. Added a screen in Mode-0 that shows the Mac motherboard eee code.

Firmware version 3.6 Fixed an issue that would occasionally cause a latch-up in some Micron ROM chips on some older Mac boards (Medusa-3 only). Updated the routine that finds the serial number in the T2 ROM to handle some changes that Apple did very recently.

Firmware version 3.7 Fixed an issue that prevent the Medusa from writing to a ROM chip that had been erased badly.

Recent changes: Medusa now warns you if the QE bit in the ROM is not set when it should have been. Now shows the complete Mac firmware version (14 characters) as Apple keeps messing with the format. Fixed two small issues that combined with Apple changing the format of data in NVRAM would cause the 'Mac Owner' to not always be shown. For Medusa-3 changed the way it detects what way round the Pomona clip is clipped onto the ROM to also accomodate 820-3588.

2021-03-28 Added support for SST ROMs as used in some older Macs. These have two quirks compared to other ROMs. The 0x02 command only allows you to write only byte as opposed to a whole page. The second is that the BP bits are automatically turned on every time the chip is powered.

Medusa now shows production date and motherboard EEE code on 16Mbit EFI ROMs.

Medusa now shows motherboard models for MacBook A1181.

Firmware version 4.0 Added the option to connect to our upcoming Listener products.

Firmware version 4.1 Improved the option to connect to our upcoming Listener products

Firmware version 4.2 Improved the handling of Adesto (T2) ROM chips. Clear Status (Mode-15) now supports Adesto ROMs. This is useful to turn off Block write Protect.  When writing to am Adesto ROM the BP bits are remembered before the writing, turned off during the writing and then, after the writing, restored to what they were originally.

Firmware version 4.3 (Now shipping) Added the option to remove DEP (Mode-9).