Reinstallation of TrueNAS fails - Error can't find partition 2 on mmcblk0

TrueNAS General
1

Dear All,

My first post here, so hope I am in the right place?

I installed TrueNAS 25.04.01 last week on my new Beelink ME Mini with 24TB of NvME SSDs. All went very well and I was operational within hours and tested my wife’s iPad’s access to a .iso file on the NAS.

Then i did something stupid and managed to block all SMB access to the device. Tried to fix the problem but to no avail.

So I thought as I had done much in the way of configuring or installing my iso library I decided just to reinstall TrueNAS from the USB stick I had used for the first installation.

It starts up ok, I select the internal memory of the device and I enter the admin password, and almost immediately I get the message that the installer can’t find partition 2 on the SSD disk?

Why would it work the first time but not the second? The device comes with Windows installed on it which I overwrote with TrueNAS and that worked, but trying to reinstall TrueNAS over TrueNAS fails?

Any help or ideas gratfully received.

Best regards, Colin

2

Before proceed make sure to wipe your boot disk, you can do It also during installation: choose to open the shell → use lsblk to identify the correct disk (take care don’t wipe something else :smile: ) → then use blkdiscard /dev/sd* -f → retry installation

3

Many thanks for your rapid reply oxyde. I used blkdiscard /dev/mmcblk0 it did not like the * for the 3 partitions. That seemed to do something but the install still gave “Failed to find partition number 2 on mmcblk0” even though lsblk clearly shows the 3 partitions.

4

It didn’t like the -f parameter even before the drive reference.

5

Realizing now that your disk Is an emmc, i think that the command did nothing and not fit your case.

When you used lsblk you see if those partition were read only?

I think that bitting the bullet and use a dd will erase the partition table, but wait a second opinion maybe there Is a fastest way

6

I have a photo of the lsblk output but I can’t upload it, is there any way.

7

Here is the OCR version…

root@truenas-installer:/# lsblk
NAME          MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
loop0           7:0    0  217M  1 loop /usr/lib/live/mount/rootfs/filesystem.squashfs
                                            /run/live/rootfs/filesystem.squashfs
sda             8:0    1 29.8G  0 disk
├─sda1          8:1    1  122K  0 part
├─sda2          8:2    1    5M  0 part
├─sda3          8:3    1  1.8G  0 part /cdrom
└─sda4          8:4    1  300K  0 part
mmcblk0       179:0    0 58.2G  0 disk
├─mmcblk0p1   179:1    0    1M  0 part
├─mmcblk0p2   179:2    0  512M  0 part
└─mmcblk0p3   179:3    0 57.7G  0 part
nvme0n1       259:0    0  3.6T  0 disk
└─nvme0n1p1   259:1    0  3.6T  0 part
nvme0n1       259:0    0  3.6T  0 disk
nvme1n1       259:2    0  3.6T  0 disk
└─nvme1n1p1   259:3    0  3.6T  0 part
nvme2n1       259:4    0  3.6T  0 disk
└─nvme2n1p1   259:5    0  3.6T  0 part
nvme4n1       259:6    0  3.6T  0 disk
└─nvme4n1p1   259:7    0  3.6T  0 part
nvme5n1       259:8    0  3.6T  0 disk
└─nvme5n1p1   259:9    0  3.6T  0 part
mmcblk0boot0  179:256  0    4M  1 disk
mmcblk0boot1  179:512  0    4M  1 disk
8

Try the commands - reboot explained here

$ echo 0 > /sys/block/mmcblk0boot0/force_ro
$ echo 0 > /sys/block/mmcblk0boot1/force_ro

Also in the same topic people talks about wiping with dd, so on that not seems i was wrong :smile: in case try It

9

Many thanks for this information Davide, I have done the following:

1: Start up ME Mini with USB stick containing .iso of TrueNAS 25.4.0
The installation starts and run up to the 4 choice menu.

2: I select Shell and use the lsblk and echo commands to make the two boot partitions RW. That works just fine.

3: I exit thhe shell and select the installation option. It starts running and almost immediately stops with the same error can’t find partion 2 on mmcblk0.

4: I hit Enter and return to the 4 choice menu.

5: I select shell and run lsblk, which shows that the two boot partions are still RW.

Please can yuo explain your DD option (destroy disk?).

10

I just reread the instructions from the post you linked to and is says restart the system and then reinstall TrueNAS.

So I just did a shutdown and restart but when I get the shell the two boot partitions are back to RO!

I try to see if there is anything in the BIOS that forces that change.

11

I have send a support request to the manufacturer, I did upgrade the BIOS but that made no change at all to this problem.

12

I think that the last thing you can try Is to wipe the disk with the dd command.

Here you find some explanation (go to the Wiping a Block Device section), but Is also mentioned in the thread above.

Otherwise, i have no more idea, i have poor experience with device like yours :smile:

13

Dear All,

By installing TrueNAS 24.04 and upgrading to 25.04 my ME Mini is now operational. I reviewed all the threads Davide sent including

Installation failed on eMMC Odroid H4+

which includes comments about my hardware and decided before plunging in modifying Python code in the installer I would try the 24.04 install and it worked. I have now upgraded to 25.04 and have restarted my configuration.

I have learnt a lot about emmc chips and their challenges!

Many thanks to Davide for your kind assistance and patience!

Best regards, Colin

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