Brand new programmable 2MB flash based ROM SIMM for Apple MAC SE/30, IIsi and IIfx.
New version with 1.27mm (50 mils) nominal PCB thickness to improve socket compatibility.
This SIMM can hold a MAC ROM plus a 1.5MB bootable ROM DISK.
SIMM can be programmed with a minimal bootable System 7.0.1 image for a totally diskless boot (press ctrl+R for ROM boot). See the third picture for the content of the default flash image.

Flash chips can be re-programmed individually with a standard flash programmer with a PLCC-32 adapter.
The SIMM is also compatible with Doug's SIMM programmer.

Free flash service available with purchase.
Replaces Apple p/n: 341-0655-A, 820-0241-B, 820-0241-02, 820-0296-B. Can be used to make the SE/30 32-bit clean. See last picture showing my SE/30 running MacOS 7.6.1

Designed and assembled in USA with all new components.
512K ROM SIMM is available in this listing

Documentation and support available at gglabs.us

1 year warranty and 30 days money back (less shipping cost) if not satisfied


We are happy to combine shipping for multiple items orders. However, due to ebay restrictions, an invoice must be requested before submitting the payment.
International buyers are welcome, however economy international shipping does not provide any tracking outside USA. If tracking is desired, please consider using International Standard which is significantly faster and provides door to door tracking to Canada, Australia, Japan, South Korea, Israel, New Zealand, Singapore, Hong Kong and most European countries. The destination country may charge customs duty and/or VAT. These charges are out of our control and must be paid by the buyer to their own government.

Shipping MethodTrackingEstimated Delivery Refund/resend After
First class (USA) Good 3-10 days3 weeks
Priority Mail (USA) Very Good 2-5 days2 weeks
Priority Mail Express (USA) Excellent 2-3 days1 week
International Economy None 3-8 weeks10 weeks
International Standard Good/None 2-4 weeks6 weeks
UPS International Saver Excellent 3-6 days2 weeks