# Upgrading Mender client 2.6 to 4.0 **URL:** \ **Category:** General Discussions\ **Tags:** mender-client\ **Created:** [January 3, 2025, 12:02pm UTC](https://hub.mender.io/t/upgrading-mender-client-2-6-to-4-0/7440 "2025-01-03T12:02:57Z")\ **Posts on this page:** 1\ **Showing post:** 18
**Author:** ![TheYoctoJester](https://yyz2.discourse-cdn.com/flex036/user_avatar/hub.mender.io/theyoctojester/32/1444_2.png) [@TheYoctoJester](https://hub.mender.io/u/TheYoctoJester)\ **Post date:** [February 14, 2025, 11:09am UTC](https://hub.mender.io/t/upgrading-mender-client-2-6-to-4-0/7440/18 "2025-02-14T11:09:52Z")
> [@Vladimir](#): > > `Image too large: increase CONFIG_SYS_BOOTM_LEN` This clearly is the killer. So the new kernel on `scarthgap` exceeds the memory which `u-boot` has allocated for loading it. Good news is that it then fails to boot, and rollback saves you. Bad news is that this is probably hard to fix in place, as reflashing an updated version of `u-boot` on live devices usually creates a single point of failure. The most practical advice would be to inspect your kernel configuration, and see if you can trim it down enough to fit into `u-boot`s loading region. Usually the default kernel configurations leave quite some leeway for such. Greetz, Josef --- _[View the full topic](https://hub.mender.io/t/upgrading-mender-client-2-6-to-4-0/7440)._