I first saw now that this was also posted here. Very great that you have made the software available :-). These softwares can be hard to track down if needed for a repair or an upgrade. I might have a go at updating my BM4500 to 2way at one point in the future. Would you happen to know if the eproms has to be the excact model or if other can be used?  

Thanks! With both BIN files you can write whichever version you want (two-way comms or the BM-as-link-room-mode only in 1.6, as you pointed out in Discord). The chip in my unit (and the replacement) was a generic 27512 EPROM, which is still readily available. Mine was M27512FI, ie. by STMicroelectronics but any manufactorer should be fine (as long it's the same 28-pin DIP package). I couldn't find the speed rating for either chips, but in this case I'd guess the "slowest" 200ns part should work (elsewhere, like vintage computers the speed of the ROM might be important). You'll also need an UV-eraser (for the old EPROMs with window on top) and an EPROM programmer. I'm sure there are also newer pin-compatible variants (EEPROMs, ie. no UV-erasing needed, or write-once chips if you just want to write a chip once and not re-use it). I find it interesting that the BM4500 was shipped with the "limiting" software (if the 2-way IR hardware was fitted). Also the release notes telling a fix for "Beosystem 4500 may intermittently block and it is necessary to remove the mains plug" sounds pretty annoying bug, and surely would've caused calls to dealers! (I might have actually experienced this on my unit with the old ROM once or twice, I always thought it was just an effect of a low battery but apparently not!)

Just wanted to say thank you to @

Location: Silicon Valley

My B&O Icons:

BeoCenter-9500.png

Beoremote-Beo4.png

Beovox.png

Beosound.png

Beosound-9000.png

Beoplay-H95.png

Beoplay-Earset.png

Thanks! I have an older MCUMall GQ-4X USB Programmer, but any EPROM programmer that supports these older DIP-chips should be able to read the ROMs. It takes a bit of effort to get into the CPU box and to the ROM chip, but one could of course replace the battery or caps while there... wouldn't hurt to replace those. The seller I bought my BM4500 two-way kit also had an BM6500 kit for sale, but the single kit was already on the expensive side with shipping so I skipped getting them both. On a related note there is currently a BM7000 ROM for sale on german eBay (https://www.ebay.com/itm/257132321336), but although the description says 1.3, the chip label says it's 1.1. Someone probably upgraded and put the old chip in the bag and the seller didn't notice.

Added now to the archive.org item: I scanned the single-page instruction sheet on where the dealer preparing the upgrade should stick the version stickers to, and most importantly the nice two-way terminal labels (to be placed on the BM and the box) 😎 Using a Dymo labelwriter, I printed myself new ones (as the NOS stickers had completely lost adhesion).

Very nice touch with the labels. Do you know if these labels only was used for the 4500 since it got new functionality or if they were also used on other two way capable systems?

I'm pretty sure I'd have seen the black two-way terminal -stickers on somewhere else but can't remember. Then again, I might be mistaking it for the similarily styled black BEOLINK sticker that can be seen on fe. BC9000's back (no two-way IR there but I presume it hints to the device communications over the 7-pin DIN connectors and/or the MCL2 system).