MiSTer FPGA Forum

Hi guys, I hope someone can help me, is there a way to update the OS without deleting the data on the SD card?

Yes.

https://mister-devel.github.io/MkDocs_M ... the-mister

Don't forget to also base your MISTer.ini on the new MISTer ini example.

Remember it's a good idea to have solid backups at all times. SD cards aren't especially reliable, especially when left unpowered for any length of time, so it's best never to be in the position where having to rebuild the Mister card from scratch will lose any data.

If you're tight on space, backing up saves, savestates, config, and maybe Scripts will generally get everything that's critical, and should take up very little space. Having a spinning drive backup of your ROMs is not a bad idea, since copying to the SD or over a network is easy and fast compared to finding and downloading everything again.

You can find the ROMs again, and you can reconfigure cores without too much trouble, but your saves and savestates are relatively precious. You can't download them and you have to invest a ton of time to re-create them. Making daily backups of those two directories would be an excellent idea.

Daily could be a bit to much i would say.
But it will offcourse depends on how much you play with yourse, sorry play with your mister

Malor wrote: ↑Thu Dec 08, 2022 2:44 am

SD cards aren't especially reliable, especially when left unpowered for any length of time

can you elaborate on this? if i haven't plugged my sd card in for say..6 months is the data unlikely to be there? if so why?

You can read some about it here.
https://www.quora.com/Why-does-flash-st ... -long-time

But basically the flash cells lose charge over time, when it has power it lose the charge slower, and the flash controller in many cases does keep checking and refresh the cell if it gets too low.
The older flash media with either 0 or 1 per cell is better, the never with 0 or 1 or 2 or even newer with 0/1/2/3 per cell gets worse since the charge level between every "level" gets smaller and smaller.
Therefore easier to lose data.

On top of that older flash media made in bigger nano-meters is also better.
On top of that one more time.
Flash chips do get sorted and the best (cost most) goes to fast ssd´s then goes second best to medium/slow ssd´s, then EMMC (flash that is soldered to motherboards/and so on), then usb drives, and sd cards dead last.
So sd cards do have the biggest change of getting flash chips that could lose charge faster then normal, combined with using the smallest chips.
Meaning cram in as much data per cell=higher risk!

One BIG example of this is the samsung 840 ssd data loss (in some cases) and slow read speed in almost all 840 ssd´s and that after 6-12 months most of them where reading much,much slower, as in some cases much slower then a spinning harddrive.
In some cases they where slow after only 2-3 months.
And that was because the cells had lost some charge combined with a bad firmware, which could be mostly fixed in a new FW.
https://www.thessdreview.com/daily-news ... cted-ssds/

woah.. thanks for that detailed explanation. total respect. I had no idea. I do backup my sdcards.. but just took it for granted that even after a few months of not being used the data would be fine..

A lot depends on the temperature when they're written, and where they're stored. Recording data while the card is hot increases longevity, but storing it where it's hot decreases it.

Generally, you just shouldn't trust SD cards for storage when they're not plugged in for any length of time. As long as they're getting power, their firmware will do occasional rewrites of aging blocks, but when just sitting there, every cell on the card is slowly losing charge. If it's really hot (50C), they can lose their charge within a couple weeks. Stored at 25C, they can maybe keep their charge for a year.

But, any data you want to keep? Don't trust SDs or SSDs. Use a spinning, old-style hard drive. You can expect data to last almost indefinitely there; the hard drive mechanisms will probably fail before the magnetic media does.