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Posted Wed Oct 16, 2019 12:48 am

Hi all,

As I am currently also working on a C64 project, I keep having an eye open for new expansions to my C64.

Very recently I got aware of a new cartridge for the C64 named "BackBit".

The homepage of the expansions is here. And of course they have a shop. They do also have a forum, of course.

Below please find an overview that I grabbed from ebay, actually. Seems pretty advanced.



Combines the best features of the 1541, SD2IEC, EasyFlash, Pi1541 and Ultimate-II+. See chart in images for comparison. New features being added all the time through firmware upgrades.

Compatible with unprotected D64 disk images, and most game conversions designed to be compatible with IDE64 (when loaded as D81). Built-in instant loading so a fast loader is not required.


BackBit C64 bare cartridge
USB Cable (for firmware upgrades)

This cartridge features:

Instant loading from D64, D71, D81, CRT, PRG, P00, T64 and BBT files
Disk access supported by KERNAL emulation
(NEW!) CRT <= 128KB fully supported
CRT > 128KB supported by emulation
Preliminary EasyFlash CRT support
Up to 4GB of data per program via BBT file format
Unlimited firmware upgradeability via USB (cable included)
“Rip & Burn” disks on your 1541
Replaceable Real-Time-Clock battery
Fully powered by your C64
Works on C128 in C64 mode
Proven compatibility with most C64 revisions

Screenshot_2019-10-16 Backbit CARTRIDGE für Commodore 64 eBay.png

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Posted Wed Oct 16, 2019 1:42 am

Hm... interesting. I have to read into it...

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Lexington VA

Posted Wed Oct 16, 2019 7:01 am

seems kinda specious and misleading to compare it to the ultimate u1541 cart. its more like a hotted up sd2iec than the u1541II.

as for "Works on C128 in C64 mode" my U1541II works in C128 in C128 mode...

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Seattle, WA, USA

Posted Wed Oct 16, 2019 9:50 am

Run/created by a lady in San Francisco. Very cool

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Zippy Zapp

Posted Fri Oct 18, 2019 1:56 pm

I have one of these and have been using and testing it for a while. It is a fantastic device. I haven't had time to write a review yet, but I intend to.

Evietron is the maker and she is very attentive to changes and is adding new things to the firmware all the time. When I first got it, it would not function correctly on my short board C64C but worked fine on my original 1983 C64. Through various firmware adjustments and lots of testing, she eventually came out with a firmware that works on all 64s. (There are some differences in 64 revisions that apparently, can cause timing critical devices to need some tweaking)

It is like an SD2IEC and an EasyFlash all in one (sort of). You can put .D64 files onto a microSD card and load them instantly into the C64 memory. While testing I used various .D64 files and was amazed at the speed, near instant loads. It also supports .CRT cartridge images. Both games and some utilities like diagnostic and dead test carts.

It also has the ability to write .D64s to a floppy as well as many other functions like its own easyflash type cartridge format that can consist of many disk images (put simply).

It is a fantastic device and one that I will be using regularly.

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