Asus AX1800U flash size question

Hello dear forum.

Recently, I bought an refurbished Asus AX1800u for using with OpenWRT. After successfully flash the OpenWRT 23.05.3 firmware (mtd-write method of AX53U), I noticed that flash size reported by Luci was only 32MB (same as df -h). I reverted to stock firmware using Asus Recovery (note that it is difficult to find&download the official AX1800U firmware) and noticed that the space reported by df was again 32MB. Officially, this router has 128MB of flash size.

This is the current (23.05.3) mtd layout
dev: size erasesize name
mtd0: 00080000 00020000 "u-boot"
mtd1: 00060000 00020000 "u-boot-env"
mtd2: 00100000 00020000 "nvram"
mtd3: 00100000 00020000 "factory"
mtd4: 00100000 00020000 "factory2"
mtd5: 03200000 00020000 "firmware"
mtd6: 00400000 00020000 "kernel"
mtd7: 02e00000 00020000 "ubi"
mtd8: 03200000 00020000 "firmware2"
mtd9: 01020000 00020000 "jffs2"

This is the report for df -h:
Filesystem Size Used Available Use% Mounted on
/dev/root 4.3M 4.3M 0 100% /rom
tmpfs 122.2M 1.1M 121.2M 1% /tmp
/dev/ubi0_1 33.0M 1.1M 30.2M 4% /overlay
overlayfs:/overlay 33.0M 1.1M 30.2M 4% /
tmpfs 512.0K 0 512.0K 0% /dev

Please, could you advise how can I "get" the advertised 128MB of flash?

I did some search on the forum and find a suggestion (actually on git) to delete the firmware partition in between flashing the openwrt. By deleting this partition, will I be able to return to stock (and by which method)?

When reverting to stock I had the surprise that everything was configured as before flashing the OpenWRT. Possibly, due to stock partition being available.

Thank you.

PS. This is my first post on this forum. I am using OpenWRT for many years but I have little knowledge about the intricacies of the image building.

you can't, ever, 128MB is the size of the flash chip.

have a look at the remark regarding flash size vs available space at

no one will know, until it's been tested, you're (?) the tester, but it'll probably get more complicated.

1 Like

It will stay as it is for now, being the main router. But, the available space is very low to be comfortable on the long run.

Maybe adding the info on the device's page that the available space will be reduce to 32MB after flashing will help other to decide about this router.

Thank you for your time.

The device isn't unique in any way, the < 50% storage applies to most devices with fixed storage space.

Only a few AX Xiaomis have gotten the space maximized.

This topic was automatically closed 10 days after the last reply. New replies are no longer allowed.