Reviving a CIDCO MailStation – the last Z80 computer
(2026/02/11)
- Reference: 1770804912
- News link: https://www.theregister.co.uk/2026/02/11/last_z80_machine/
- Source link:
FOSDEM 2026 Michal Pleban knows his old kit inside out, and his talk on the CIDCO MailStation was one of the most interesting of FOSDEM for us – as well as the funniest.
Pleban's talk, " [1]Hacking the last Z80 computer ever made ," was more than just a dive into retro computing. It also explored some of the many strange decisions involved in launching a [2]new range of hardware based on the eight-bit Zilog Z80 chip in 1999 – when the 16-bit computer era was largely over, and just a couple of years before 32-bit x86 chips would be replaced by x86-64.
A couple of years ago, Zilog [3]discontinued the standalone Z80 processor , bringing a nostalgic tear to the eyes of many a senior geek, including The Register's [4]Rupert Goodwins . If there were pub quizzes aimed specifically at graying techies, a good question might be "what was the last ever Z80 computer?"
[5]
The [6]CIDCO MailStation , also sold in the US as Earthlink's Mivo 100, is a strong contender. Launched in 1999, [7]Time Magazine reported on the final model , the cordless Mivo 350 – which is [8]still listed on Amazon . While writing this, we found units for sale on eBay US for under $26 – or less than $12 if you don't mind an untested one.
[9]
[10]
As Pleban put it, it's a late-1990s "internet appliance," sold under the tagline of "Email made easy." That slogan might have proved a tad ambitious as the slogan was replaced on later models' packaging by "Email without the PC."
Its specifications are good for an eight-bit machine. It's a self-contained unit, with a 320 x 128 mono LCD, a 12 MHz Z80 with 128 KB of RAM, and a bit over a megabyte of flash. Aside from its dial-up modem, the only way to get anything in or out of it was over a Laplink cable attached to its bidirectional parallel printer port.
[11]
But it is an internet appliance, only really intended for sending and receiving email. So the $64 question (we really wouldn't pay more) is: is it a computer? It has a keyboard, a screen, some storage, some communications, and it can run apps (if you allow a generous definition). Pleban's most telling point, though, is that you can hack it.
He proceeded to detail how. The first method he explored was via the Yahoo ! icon on the home screen. This shows, or rather showed, headline news stories. What's remarkable is how it shows the formatted news stories. There's no markup format to handle bold, italics, fonts, and so on. The machine arguably doesn't have the resources.
No, each page of news is a bitmap rendered by a tiny program. Every day, the service emailed you a new app. This is a daily email with an executable attachment and it's opened for you directly; it never hits your inbox. This innovative way of updating a remote device is even [12]patented . The email attachment is encrypted with the [13]SDES algorithm . Originally intended as a teaching tool rather than for real-world security, this uses a ten-bit key – so to decrypt something, just generate all 1,024 possible keys and try them. Yours will be in there.
[14]
This would be ridiculously easy to exploit, but there's a snag. You need to activate an account via a telephone call to the United State to a service that was shut down in 2011.
[15]How the GNU C Compiler became the Clippy of cryptography
[16]Matrix is quietly becoming the chat layer for governments chasing digital sovereignty
[17]Containers, cloud, blockchain, AI – it's all the same old BS, says veteran Red Hatter
[18]CentOS is coming to RISC-V soon if you have the kit
So Pleban moved on to the second method. It's possible to dump the device's firmware, which reveals text strings relating to software updates. That means that it can be updated. It's even documented, and the documentation only runs to about ten pages. It uses a Centronics Laplink cable – not the [19]modern Laplink cables , which are much faster. The slight snag here is that very few computers have Centronics ports any more. (Before you ask, no, a USB adapter won't work.)
Then he moved on to the third method. The device has a diagnostics menu, accessed by pressing Ctrl + Shift + T while turning it on. Press Shift + 5 and you get a hexadecimal viewer of the ROM code. Another keystroke makes it into a hex editor, so you could manually rewrite firmware. If you have a very [20]steady hand anyway.
Inspection of the ROM reveals that there's a 64-byte loader that accepts new ROM code over the parallel port. With that, it's time to do one's best Matthew Broderick impersonation and say [21]"we're in!" .
One of the chief snags with this approach is that there are no checks or validation steps when uploading a new ROM. One error and the machine is bricked. There is no recovery procedure to get back from bad firmware. During the Q&A session, an audience member asked Pleban how many MailStations he had killed in the process of researching the talk. He reluctantly admitted that he now had three dead ones but that was OK – he had another eight spares. He also brought two boxed units to the talk, and gave one of them away at the end.
This is an interesting little machine for those who enjoy low-level hacking, and he estimates the companies sold hundreds of thousands of them. Pleban himself offers various resources for aspiring MailStation hackers: an [22]emulator for testing your code, a [23]host application to transfer software to the MailStation, and [24]hardware documentation .
The Reg FOSS desk is quite interested in this sort of thing, and we hadn't heard of this device before. However, other people have been hacking on them for some years now and we found quite a bit of resources and information, from the [25]Fybertech page about it to Josh Stein's page about using it as a [26]Z80 development platform . He's even built a [27]Wi-Fi interface for the thing . "Dr Francintosh" is working on [28]giving it a Raspberry Pi brain transplant . ®
Get our [29]Tech Resources
[1] https://fosdem.org/2026/schedule/event/FEHLHY-hacking_the_last_z80_computer_ever_made/
[2] https://web.archive.org/web/20070310230102/http://www.findarticles.com/p/articles/mi_m0BDW/is_23_41/ai_62918954
[3] https://www.theregister.com/2024/04/22/z80_cpu_end_of_sales/
[4] https://www.theregister.com/2024/04/29/opinion_z80/
[5] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/personaltech&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aYxhUFhzYlAHtEM-pbQ2MQAAAEs&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[6] https://en.wikipedia.org/wiki/Cidco_MailStation
[7] https://time.com/archive/6665516/in-brief-dec-24-2001-2/
[8] https://www.amazon.ae/EarthLink-Mivo-Cordless-mail-Appliance/dp/B00005O0KW
[9] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/personaltech&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aYxhUFhzYlAHtEM-pbQ2MQAAAEs&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[10] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/personaltech&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aYxhUFhzYlAHtEM-pbQ2MQAAAEs&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[11] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/personaltech&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aYxhUFhzYlAHtEM-pbQ2MQAAAEs&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[12] https://patents.google.com/patent/US6697942
[13] https://github.com/Sahil-4555/Simplified_DataEncryption_Standard_SDES
[14] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/personaltech&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aYxhUFhzYlAHtEM-pbQ2MQAAAEs&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[15] https://www.theregister.com/2026/02/09/compilers_undermine_encryption/
[16] https://www.theregister.com/2026/02/09/matrix_element_secure_chat/
[17] https://www.theregister.com/2026/02/08/waves_of_tech_bs/
[18] https://www.theregister.com/2026/02/05/centos_coming_to_riscv_soon/
[19] https://go.laplink.com/cables
[20] https://xkcd.com/378/
[21] https://www.youtube.com/watch?v=E-AyusLQU9M
[22] https://github.com/MichalPleban/mailstation-msemu
[23] https://github.com/MichalPleban/mailstation-mailtransfer
[24] https://github.com/MichalPleban/mailstation-hardware
[25] https://www.fybertech.net/mailstation/
[26] https://jcs.org/2019/05/03/mailstation
[27] https://jcs.org/wifistation
[28] https://drfrancintosh.wordpress.com/cidco-mailstation/
[29] https://whitepapers.theregister.com/
Pleban's talk, " [1]Hacking the last Z80 computer ever made ," was more than just a dive into retro computing. It also explored some of the many strange decisions involved in launching a [2]new range of hardware based on the eight-bit Zilog Z80 chip in 1999 – when the 16-bit computer era was largely over, and just a couple of years before 32-bit x86 chips would be replaced by x86-64.
A couple of years ago, Zilog [3]discontinued the standalone Z80 processor , bringing a nostalgic tear to the eyes of many a senior geek, including The Register's [4]Rupert Goodwins . If there were pub quizzes aimed specifically at graying techies, a good question might be "what was the last ever Z80 computer?"
[5]
The [6]CIDCO MailStation , also sold in the US as Earthlink's Mivo 100, is a strong contender. Launched in 1999, [7]Time Magazine reported on the final model , the cordless Mivo 350 – which is [8]still listed on Amazon . While writing this, we found units for sale on eBay US for under $26 – or less than $12 if you don't mind an untested one.
[9]
[10]
As Pleban put it, it's a late-1990s "internet appliance," sold under the tagline of "Email made easy." That slogan might have proved a tad ambitious as the slogan was replaced on later models' packaging by "Email without the PC."
Its specifications are good for an eight-bit machine. It's a self-contained unit, with a 320 x 128 mono LCD, a 12 MHz Z80 with 128 KB of RAM, and a bit over a megabyte of flash. Aside from its dial-up modem, the only way to get anything in or out of it was over a Laplink cable attached to its bidirectional parallel printer port.
[11]
But it is an internet appliance, only really intended for sending and receiving email. So the $64 question (we really wouldn't pay more) is: is it a computer? It has a keyboard, a screen, some storage, some communications, and it can run apps (if you allow a generous definition). Pleban's most telling point, though, is that you can hack it.
He proceeded to detail how. The first method he explored was via the Yahoo ! icon on the home screen. This shows, or rather showed, headline news stories. What's remarkable is how it shows the formatted news stories. There's no markup format to handle bold, italics, fonts, and so on. The machine arguably doesn't have the resources.
No, each page of news is a bitmap rendered by a tiny program. Every day, the service emailed you a new app. This is a daily email with an executable attachment and it's opened for you directly; it never hits your inbox. This innovative way of updating a remote device is even [12]patented . The email attachment is encrypted with the [13]SDES algorithm . Originally intended as a teaching tool rather than for real-world security, this uses a ten-bit key – so to decrypt something, just generate all 1,024 possible keys and try them. Yours will be in there.
[14]
This would be ridiculously easy to exploit, but there's a snag. You need to activate an account via a telephone call to the United State to a service that was shut down in 2011.
[15]How the GNU C Compiler became the Clippy of cryptography
[16]Matrix is quietly becoming the chat layer for governments chasing digital sovereignty
[17]Containers, cloud, blockchain, AI – it's all the same old BS, says veteran Red Hatter
[18]CentOS is coming to RISC-V soon if you have the kit
So Pleban moved on to the second method. It's possible to dump the device's firmware, which reveals text strings relating to software updates. That means that it can be updated. It's even documented, and the documentation only runs to about ten pages. It uses a Centronics Laplink cable – not the [19]modern Laplink cables , which are much faster. The slight snag here is that very few computers have Centronics ports any more. (Before you ask, no, a USB adapter won't work.)
Then he moved on to the third method. The device has a diagnostics menu, accessed by pressing Ctrl + Shift + T while turning it on. Press Shift + 5 and you get a hexadecimal viewer of the ROM code. Another keystroke makes it into a hex editor, so you could manually rewrite firmware. If you have a very [20]steady hand anyway.
Inspection of the ROM reveals that there's a 64-byte loader that accepts new ROM code over the parallel port. With that, it's time to do one's best Matthew Broderick impersonation and say [21]"we're in!" .
One of the chief snags with this approach is that there are no checks or validation steps when uploading a new ROM. One error and the machine is bricked. There is no recovery procedure to get back from bad firmware. During the Q&A session, an audience member asked Pleban how many MailStations he had killed in the process of researching the talk. He reluctantly admitted that he now had three dead ones but that was OK – he had another eight spares. He also brought two boxed units to the talk, and gave one of them away at the end.
This is an interesting little machine for those who enjoy low-level hacking, and he estimates the companies sold hundreds of thousands of them. Pleban himself offers various resources for aspiring MailStation hackers: an [22]emulator for testing your code, a [23]host application to transfer software to the MailStation, and [24]hardware documentation .
The Reg FOSS desk is quite interested in this sort of thing, and we hadn't heard of this device before. However, other people have been hacking on them for some years now and we found quite a bit of resources and information, from the [25]Fybertech page about it to Josh Stein's page about using it as a [26]Z80 development platform . He's even built a [27]Wi-Fi interface for the thing . "Dr Francintosh" is working on [28]giving it a Raspberry Pi brain transplant . ®
Get our [29]Tech Resources
[1] https://fosdem.org/2026/schedule/event/FEHLHY-hacking_the_last_z80_computer_ever_made/
[2] https://web.archive.org/web/20070310230102/http://www.findarticles.com/p/articles/mi_m0BDW/is_23_41/ai_62918954
[3] https://www.theregister.com/2024/04/22/z80_cpu_end_of_sales/
[4] https://www.theregister.com/2024/04/29/opinion_z80/
[5] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/personaltech&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aYxhUFhzYlAHtEM-pbQ2MQAAAEs&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[6] https://en.wikipedia.org/wiki/Cidco_MailStation
[7] https://time.com/archive/6665516/in-brief-dec-24-2001-2/
[8] https://www.amazon.ae/EarthLink-Mivo-Cordless-mail-Appliance/dp/B00005O0KW
[9] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/personaltech&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aYxhUFhzYlAHtEM-pbQ2MQAAAEs&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[10] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/personaltech&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aYxhUFhzYlAHtEM-pbQ2MQAAAEs&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[11] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/personaltech&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aYxhUFhzYlAHtEM-pbQ2MQAAAEs&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[12] https://patents.google.com/patent/US6697942
[13] https://github.com/Sahil-4555/Simplified_DataEncryption_Standard_SDES
[14] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/personaltech&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aYxhUFhzYlAHtEM-pbQ2MQAAAEs&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[15] https://www.theregister.com/2026/02/09/compilers_undermine_encryption/
[16] https://www.theregister.com/2026/02/09/matrix_element_secure_chat/
[17] https://www.theregister.com/2026/02/08/waves_of_tech_bs/
[18] https://www.theregister.com/2026/02/05/centos_coming_to_riscv_soon/
[19] https://go.laplink.com/cables
[20] https://xkcd.com/378/
[21] https://www.youtube.com/watch?v=E-AyusLQU9M
[22] https://github.com/MichalPleban/mailstation-msemu
[23] https://github.com/MichalPleban/mailstation-mailtransfer
[24] https://github.com/MichalPleban/mailstation-hardware
[25] https://www.fybertech.net/mailstation/
[26] https://jcs.org/2019/05/03/mailstation
[27] https://jcs.org/wifistation
[28] https://drfrancintosh.wordpress.com/cidco-mailstation/
[29] https://whitepapers.theregister.com/
Laplink
ICL1900-G3
Wow! I'd completely forgotten about it. In its day, it was very useful.
"very few computers have Centronics ports any more"
I recently picked up a combined serial (com)/parallel (lpt) PCIe card (for the com port) so they were still being made; up to a few years ago.
Servers often have serial ports so a workstation equipped with one of these cards can make managing headless servers a bit easier.